Why do I want to look like everyone else.
While I'm all for arguing over the benefits of following fashion or going it alone, the OPs specific question was:
What white trainers are currently "in"? (Not that it matters, but I would like to know)
So in that sense I can understand why some posters (including me!) answered the way they did? And loads of posters also gave ages too because op didn't make it clear and there is obviously a difference between what's "in" for each group?
If OP had asks for recs on the comfiest / most affordable / best looking / longest wearing / all time favourite trainer... I don't think anyone would have said "that's not 'in' for my age group"
So why the decent into "why would I want to look like everyone else?" territory when the OP was literally asking what white trainers to buy if she wanted to look like everyone else 
20 somethings still look like they're all marching around in uniform to me. I suppose it's not that long since they left school and it takes them a while to lose that tribal badge requirement in their choices.
Honestly just sounds snidey to me.
Everyone is perfectly entitled to hate on the "in" trends btw. My "out" skinny jeans will never be given up, just like certain posters "out" trainers. But some people like to follow fashions / trends for certain items and I think that should be a totally valid thing to want on a board about style & beauty. 