Main roles of the support?

I'm a lowly silver (who did not bother with ranked after my promos) who seems to have some sort of absurd and narrow view on supports. Mind you, I have mained support since day one. My perception of the support is to protect, harass early to win lane, provide vision, and set up kills not for myself, but for others (especially my AD carry). And out of those (I'm sure there are a couple more), I believe that protecting is the main and foremost important job of the support. I thought that the main reason the support even exists and goes bottom lane is that the ADC needs a support to sustain in both early and late game. They have the potential to dish out the most damage, yet they are also the squishiest of the team. ** "I think you're misunderstanding the role of Vel'Koz support. His job isn't to protect the carry. "**

I am currently having a discussion in another board for believing that a Vel'Koz is not a very well-suited partner for an AD Carry, especially ones such as Sivir who have short ranges and no reliable method of escape (her R is nice, but it won't help her that much when there are three people trying to kill her simultaneously). I simply dislike the poor peel-aspect of a Vel'Koz support. People say that "Damage is the best cc," but I highly doubt that an underfed Vel'Koz can triple kill the ones who are on his carry in the matter of a few seconds. While he's popping his ult at them, they can simply turn to his direction, kill him in one second (gap closers) , and turn back to his carry.

If protecting is not the main role, then why am I flamed at when I lock down the enemy carry as Thresh (instead of protecting my carry) when no one else is going after him or her? It's not like I'm standing idly while my team is dying.

Also, I was debating against many for believing that out of all the players in a team, the support should be the one doing the heavy warding and vision denial with a Sightstone and oracles (preferably having four wards on the map at all times). Yes, I know, the others should upgrade their warding trinkets to aid in vision control and buy occasional pinks. However, although that gold sounds like nothing for those who can bathe in money, there are often times when one would rather buy something more expensive and leave fountain with less than 100 or 250g to spare. Even if the others cannot (or in lower elos, DO not), ward as much as they should, it is imperative for the support to at least have vision in the key points of the map (dragon, baron, etc.). I believe that vision is an essential and one of the most basic parts of supporting. If someone is learning how to support, I believe they should be taught that they need to ward the most heavily. If not, I feel like it's the equivalent of going into Calculus without knowing what the hell Algebra is.

tl'dr Is the idea that the support's main roles are to protect and provide vision too radical? Is it too narrow-minded? How would you guys define the role of a "Support?"