I think it sums up to this:
Top lane is, and has always been, the lane most controlled by counter picks. They exist in top lane like they don't elsewhere, largely because of large disparity between ranged auto attacks, ranged abilities, sustain, and mobility, present in the top lane.
You don't get real counters in the bot lane. Even if Morgana does well against Leona due to black shield, it doesn't make it so the enemy ADC needs to give up a lot of CS. Dodge morgana's Q and you can CS as you like. Likewise any two ADCs can both last hit relatively safely against each other - with the need to back up and give up CS only arising when your support isn't present to help you.
Mid lane likewise sees no such disparity. There may be really tough matchups for some champions, but in general champions can CS from range and don't need to have a laning phase that feels like you're constantly just trying to survive and do nothing else (at least not due to the champion, you can die and start to feel this way because you're behind).
Top lane though - there are simply too many matchups where through no fault of your own, the lane immediately becomes a "do not die and try to not lane your lane opponent get fed off of you or roams in laning phase". In itself that's not a huge problem - a tank is going to outscale that Jayce or Kennen or Pantheon top laner. The ranged/harass top laner is going to 'enjoy' their early game more as they try to create a lead, and theoretically you should enjoy the mid-late game more.
The problem that arises is with how snowbally the game is, it's simply not viable to be a melee-only top laner hiding under turret against a Jayce/Kennen/Pantheon/etc... for all laning phase, because the game then gets decided by which bot lane wins. If the enemy bot lane is beating your bot lane, you lose the game. Your lane opponent literally got to win for free because he picked a champion that you can't fight in lane. If he was playing a melee champion, you could have the chance to be the better player and out-cs him and get solo kills on him and be strong enough to stand up to the enemy bot lane. Instead, you're relegated to lower-than-normal income due to being forced to give up CS AND the enemy bot lane is fed = you can't win, even though you played properly. There's a feeling of helplessness in those games, and that's a problem.
I never get the feeling as a mid laner that my bot lane fed too hard and there's nothing I can do to win. I could have won mid lane harder and roamed harder on the enemy bot to keep us in it. Likewise as a jungler I could have had better presence bot lane (although when your bot lane is a combined 0/4 before you're level 3... well those games are lost hopes no matter what). As a top laner though? Sure, if my opponent is playing a melee champion I can feel like I could have own lane harder and TP'd down to help or something. If my opponent is a Pantheon/Jayce/Kennen though, nope, no luck. There's literally nothing I can do in a game where my opponent has that much priority on me by default and my bot lane happens to lose. And it's not a two-way street, because if their bot lane is losing they can still go super aggressive on me and get fed on me if I don't play it right, and they can be strong enough to beat my bot lane. Not the other way around though. Sure, I may have an edge if the game is close and we make it to late game, but even though we'll have a superior teamfight the late-game is often more decided by better macro play or whichever team successfully gets a pick / wins a fight at baron. I might get an edge, but they're nowhere near as useless in late game as I am helpless in the early game.
are all "Fighters" and doing well right now."
