The issue with low elo support players

Hello, Before I start my rant, I have been playing league for about a year and a half. I really enjoy the game, my favorite positon to play has always been bottom lane/ADC. During my time playing the game, in solo que i've noticed that it is really hard to find someone who fully undertands what champions are actualy viable as a support. I feel like I need to adress that my acount's current rank is Bronze II 48 LP 70-ish wins, and my mmr is somewhere in high bronze to low silver. I also feel the need to say that I do not deserve to be in challenger or anywhere higher than my current rank, although I may be very salty at the time writing this I do belive that the points im trying to get across have some merit. The first thing that is most apparent in my games in particular is the rate at which my team's support player picks a mid lane mage, such as, Neeko, Ahri, Veigar, Lux (I will talk more indepth about her later). I have no issues with flex picks or "off meta" picks, but I cannot stand behind being paired with a Lux support running dark harvest building magic penetration and AP (yes, this has happened). The issue with those styles of picks can being detrimental to a team's success when they have no form of utility such as healing and shielding, back bone in a teamfight as opposed to more magic damage. In reality when a support goes down the route of picking a mid lane mage buying a spelltheif's then building only magic pen, they aren't really a support, they are just a carry with a support item. I try my hardest not to dodge or ban out a teamate's champ in draft, but sometimes I feel the need to dodge or ban out my support's pick when they want to play Lux or Neeko, because i feel like i already know how they are going to play the game. They are going to run runes like electrocute, dark harvest, or arcane commet, then buy a spelltheif's at the start of the game and not finish it/ sell it later and then build magic damage. I fell like i behave this way in draft because I have been conditioned to think that all mage supports are bad supports, and I feel like that mentality resinates a lot with other ADC players. I also know that not evry mage support is a bad support because champions like Janna, Nami, Sona, Yuumi can work really well with some teams and can serve as a really good back line healer, or offer a lot of utility such as slows, stuns, engages/disengages roots etc. Earlier I referenced Lux as mid lane mage, I do belive she can be effective as a support, but i do not think her primary role should bas as a support. I feel that way because when i play with Lux on my team I feel like they do not play her as a support, regardless if she is played in the support role. Another reason why i do not feel like she should not primarily be a support is because the game doesnt recogise her as a support. Her kit doesn't offer the same utility as other mage supports 3/4 of her abilities are designed to do damage and her one ability that doesnt do damage is upgraded last. It also doesn't help her case when Lux player build damage items like deathcap, luden's and morellonomicon over items like redemption ardent censer, and Athene's, or better yet a fully upgraded spelltheif's. my question is now, do you think i am wrong? If so, comment telling me why.