Does normal means that you can run down mid just because three of you are pre-made?

This happened today at my game when I was trying out for the new morgana after rework with w. At about 10 min of the game, I looked at my bot and their turrets are gone. This is in gold elo, so I said that "why are you inting". I mean, if your sup is 0/5 and you are 1/4 in a normal gold game, I dont see the logic. People suppose to learn their lesson. Then, his premade (lee) said "who cares, its normal". I am pretty mad because if "normal" is the excuse of inting, then, why do the people (like me, who wants to actually play it half-serious) need to suffer from their inting? I am not challenger and I said :" then run down mid if you dont care". And they did. Here are the match history. They are 3 premade so reports wont work. Happened on me more than once. I am not mad at the first time. This time, it's 3 people inting together. Just look at their band name and you will find out. I am a person with 5 honor who does not get mad. I found that excuse nonsense and if that is the excuse of inting (or having a bad day), at least dont just say "oh I dont care because its normal". It actually tilts people. Anyone with similar experience than me? I am g4 and this happened in a gold-silver game which Lee bought mobility boots and talisman to run down mid with his buddy draven and zoey.