As a jungle main myself, I will say that you have to evaluate the situation better than just "never gank a losing lane." Typically, putting winning lanes even further ahead and letting them snowball to carry you is better than investing time into losing lanes, but it's always best to evaluate a few things.
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Why is my laner losing? If it's from jungle pressure, and not as much from personal mistakes beyond warding, it may be worth it to put some investment into them. However, if it is them losing the 1v1 or 2v2, they're likely not going to do much in the game and it's typically better to try to snowball the other 2 lanes. A jungler can't be everywhere at once very easily, except for maybe a couple with extreme amounts of map mobility.
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What picks are they? If your laner counters the enemy laner, or if you just have more ways to deal with the enemy laner than they have to deal with you, it may be a good idea to gank them. You have to base it on success likelihood, and giving the opposing laner a double kill means that that lane is officially over for the rest of the game. If the enemy laner kills you in a 2v1 or 3v2 scenario, there is nothing more you can do to help them beyond just getting yourself strong, and certain picks can 2v1 or 3v2 extremely well. I'll use a recent game I played on Kled top as an example (https://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2782716093/37766829?tab=overview Match history link), the enemy Rengar kept coming top lane and I double killed them every time. I ended 17/7 with them surrenduring after I killed all of them solo. This is the perfect example of when the Rengar shoulda just left his laner, being Amumu, to play safe and farm instead of trying to kill me. Not even just my strength, but the Amumu pick as well, being Amumu top, is very weak in the early game and can just build full tank and be a monster for late game regardless. The only worry for the enemy team in this game was me getting fed, which the Rengar ganks only furthered.
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How far behind is my laner? What items do both players have? If the enemy Irelia has a Trinity Force already while my Fiora has a Tiamat, I'm not touching that lane because Irelia can probably 2v1 us pretty easily.
Now comes the inevitable question of, what about when all your lanes are losing? Again, evaluate the situation. A Shyvana or an Udyr can just farm for a bit and help protect turrets until they get strong, but they shouldn't go for kills if the lanes are losing excessively. Meanwhile, if you're playing, say, a Shaco, and you get outjungled, you're screwed. There's nothing you can do if your lanes are that far behind before you're able to start your snowball. If your teammates have a much better late game than the enemy team, it might be worth it to just try to help them turtle and scare the enemy laners off so they don't take turrets, but for the most part, let them farm up and help ensure that they don't fall further behind; do NOT go for kills. If your team has more power at 3+ items than the enemy, even if you have to sacrifice your own gold as a jungler, your own camps to the enemy, help them farm more safely to get to that spike and then overtake them. If the enemy team outscales you AND your entire team is behind, accept the loss with grace because there is nothing more that you can do, and watch it back, try to find some mistakes you may have made. Could you potentially have prevented a gank by putting a ward there? Possibly counterganked and turned a bad situation into a good one? (This from the jungler's perspective, by the way.) Was there anything you could have done to prevent the enemy team from getting this lead on yours?
That being said, there are also ways that laners can change up their playstyles to come back from early deficits. Particularly, focus on farming instead of on killing your opponent, or take smart roams if you're a champion who can roam effectively. Also, not tilting is definitely a good thing to keep an eye on. Looking at your match history, your jungler was a 6/8/4 full tank Maokai. Him having 6 kills isn't a good thing, and not feeding them to his team was a mistake by him. However, here's a question: what were that Jaurim's Fist + Ruby Crystal going to build into? Frozen Mallet? You're playing an ADC, and one who basic attacks very slowly and gets more effective movement speed than the slow from Mallet will gives you on crits, making building crit more effective for kiting. The enemy team also had basically 4 assassins. No amount of extra health OR kiting is gonna save you from them. All you can really do in that situation is either build full crit and pray you outburst them or not pick Jhin if you knew what the enemy team comp was. Kai'Sa is also a VERY powerful champion right now, and I would highly recommend banning her if you're not going to pick her. She needs some nerfs to take her down a few notches after the marksman item update, and she has been among the higher win rate ADCs with a decent play rate patch to patch since her release. She's decent in early game, strong enough to outshine most other ADCs, she's strong mid game, and she's beastly in late game. She's stronger than most other ADCs at every stage in the game. Her weakest point, being her early game, is really bad, but the right support can enable her to outshine the enemy bot lane even then because of her synergy with CC. Yes, your jungler did make mistakes in this game, but don't look at only that player. You could have played better, too, and you know it. And I know that you're going to downvote my comment because this is something that people who just blame the jungler all the time don't want to hear.
