Tanks should be doing 0 damage

all champs are required to do some damage

By this point it's hard to tell if people like you are serious or not lol

the only time i've done half of my victim's hp as alistar is if i throw everything including the kitchen sink at them

This isnt an MMO where the thing the tank is attacking is dumb enough to just focus the tank only all fight, you literally cannot have a tank do 0 damage in a PvP game and succeed. You would make tanks completely unplayable by default, especially since, you know, they kinda need to lane against something. If they cant threaten their lane opponent, what do you think will happen?

If this is the case bruisers of all sorts shouldn’t be doing assassin level damage.

I'm sorry you have a penchant for getting yourself in such bad situations where a support alistair can kick/headbutt/pulverize/trample your butt. However, the part that which forces people to focus on tanks is the fact they can do damage if you ignore them, plus CC to disrupt damage output in teamfights.

Actually it's completely normal. And Alistar is a very poor example as he's literally one of the worst damagers as a tank. A better example would be malphite who can ult 1 shot an entire team if u build him AP.