Why do i see people hating on mage supports and even when they know it works

So when i get autofill into support, i always brand support. Out of the 5 games in my ranked adventures that has happened, i lost 1. But when i do i see people saying shit like don't Brand support or even you fucking noob, brand isn't a support. If the ADC fails and you picked a mage support, you are basically a backup carry. You still don't take care and you poke the the enemy laners down. Some even have decent peel like zyra and brand ults. If they fight in the circle, they get cc'd or if they don't run away, they just watch a Michel bay movie on their health bars. Veigar's stun is good for peeling since he can trap them and the ADC car run away. Annie can easily cc 3-5 people focusing your carries. But anyways the point is it works and also I'm not sure if this still the case but adc's suck in S7. Also if you look at DotA, there's a plethora of supports who have high damage nukes and that's their main thing. Like if you look at skywrath mage, he has an ability that weakens magic resist by a fuck ton and sciences and the rest of his abilities are all nukes and one of them slows. To be fair, the way lanes work in DotA is kind of different where there's usually 3 people in the safelane (a carry and 2 supports) against one person in the offlane where the supports just try to harrasing the offlaner and stack/pull jungle camps to keep the lane from pushing. Stack means you pull the monsters out of the camp and if done at the right time more will spawn it that camp. Pulling means you pull them into the lane to agro your creeps on them. The offlaner are either extremely tanky or has good escapes and don't need alot of gold. For riadiant safe lane is bottom and dire it's top. For offlane it's raidiant top and dire bot. Anyways the point is they have alot of nukes. It also works in lol minus the 3v1 and the whole stacking and pulling mumbo jumbo. But what i don't understand is why do people hate on it when it actually works and people play whatever champion they want that works for the role they are playing.