PSA: What a Support is
Support In League is: The player assisting ADC through early game so that they can farm safely and become relevant from mid to late game.
Meaning- While "normal" supports (braum/nami/lulu/leona) are acceptable, they are not IT. Ideally, you actually want a hyper carry or an assassin as a support. "Support" harasses the enemy adc and denies them farm and delays their relevance if not staving it off entirely. Oh, still figuring out that assassin part?
Assassin: The champion type that thrives off of kill pressure and having lane bait.
Your ADC farms, you beat the other one up. So easy, so simple. Mages have already moved down to support (brand/vel/malz/lux), assassins are coming. Eventually bruisers. The meta is changing, straight supports stopped working when wards were limited to 4 a person (3 green, 1 pink). They were practically asking to be obsolete when dragon granted buffs instead of money. Supports were meant to STALL so your team could grab dragon safely and get worldwide $$$. Now it gives buffs, so you want serious powerhouses. But the meta is for another thread that I may or may not post.
tl;dr: Demanding your support to build a sightstone is pretty odd, especially since on 250g they get one via trinket. Demanding your support to not be someone who can protect you by killing for you is also counter productive- you don't need kills, you need cs.
Have a wonderful day, thanks for reading. Thoughts/questions down below, feel free for either.
or 
, either of which are enormously helpful throughout the game (I prefer the yellow myself). Are the stats on it crap? Definitely. But taking up a trinket slot that can go to dedicated enemy ward detection or continuous pink wards just to avoid shelling out 800 gold makes very little sense.
and hold enemy champions down so the ADC can (somewhat) safely beat the living tar out of them 
. The ideal arrangement in lane is to have the ADC get the kills AND the CS; gold items literally exist to make up for the difference, not perfectly but to an extent. Why do you think all three of the main gold items have final builds that don't (with the slight exception of FoTM) require stats to be used? Because the designers assumed their end users wouldn't have very good stats. A good support focuses on utility over stats: yeah, Blitcrank's and Thresh's Qs scale off of AP. Does this matter? not really. Because their Qs are not meant to be used as damaging attacks, they're intended for CC.
; these champs are likely why 
is a thing. Most assuredly if you are playing those guys you want to poke whenever you are free to. But don't obsess about it.
One of my gold friends did Brand, I don't own him yet =(.