Has anyone noticed tanks are broken???

So ive played league for a long time and ive spent countless time deciding what to build and what runes to use to best give damage as well as sustain my hp. However ive noticed that tanks DONT HAVE TO BUILD DAMAGE. what I mean by this is that a tank champion can build full tank items and still come out doing more damage than the adc who has nothing but damage items. Seemingly this doesn't seem to be an issue for anyone and most would just start playing tanks. however this difference in the game is completely unfair to other players and honestly ruins a large concept of the game... for example, An adc builds damage items, because of this he is squishy and very easy to kill. Having to sacrifice hp and survival capability for damage. However for a tank their is NOTHING being given up. Build tank items and you deal massive damage while continuously gaining more hp and being a ridiculous pain to kill.. As league is very fun I don't feel like giving it up. but when all the items you normally have to work for to get damage aren't required for a tank to one shot you.. it doesn't even seem like a game, more like a one sided slaughter where you cant kill the opposing team even tho the damage indicates you deal 500 more damage than them and they don't loose a sliver of hp while they are one shoting your entire team.