Brand and zyra are not supports.

so why can tanks and ranged carries be played in other lanes but mages can't?

they are supportive mages that were designed to go bot

Coming from a support main, brand is a support. He does assloads of damage but is very squishy, which is easily punishable by Thresh or Leona or Braum. Brand's passive instantly gives him all of the gold from spell thiefs procs, and his contribution to late game team fights from damage along with aoe slows make him one of the best supports in the game right now. Sorry, but it's the truth and you need to accept it.

My issue with brand and zyra is they build no AP yet 100-0 anything that movies

And you are a good player.

You can make the case that is not a support, because he really does not have anything supportive in his kit. He is just a damage mage that can zone well in the bottom lane with a stun (he initially started going bottom because his stun duration was A LOT longer).

Pros take him down there sometimes and that's why Brand support is acceptable.

Zyra IS a support though and is a weaker mid laner. Brand can hold his own in the mid lane but Zyra has some trouble with farming, always shoving, and is highly susceptible to ganks. If you play around her plants she actually is pretty vulnerable in the mid lane while is a real damage threat if a gank comes and his ultimate is up.

Zyra has a root, a knockup, and can zone.

For the record I play sometimes in the mid or bottom lane, but it really just depends on the matchup. I think Brand is a great champion, but against a hyper mobile comp or a tank in the bot lane like who can engage at will, he is vulnerable.

I don't like playing Brand support, but I must admit he does fulfill the basic requirements.

What he lacks in peel he makes up for in early zoning and damage, letting his ADC farm in peace.

quit being a slave to the meta, bot lane is for who ever wants it.