There are two distinct groups: those who want to blend in and those who would prefer to stand out. Wherever you fall on the spectrum, you are influenced by ideas of popular culture. Of course, where there is popular culture, there will be an opposing force. That is fine. Without diversity in thinking, innovation would never occur. 
Over my lifetime, I have noticed a group of people whose common trait is an obsessive hate of anything mainstream. Chances are, you have seen them everywhere: those who refuse to take you seriously just because you follow trends. These people are, frankly, exhausting. 
Popular culture is popular for a reason. Just because something is generally well liked does not mean it is bad. You do not have to always be at the cutting edge of innovation.  
Often, things commonly viewed as basic have stuck around for a reason: the product is successful because it works. 
Athleisure, athletic clothing that can be worn in-and-outside of the gym, has seen an astronomical rise in popularity in the modern age. This could be because athleisure is comfortable and logical in many circumstances. In Mississippi, where temperatures are regularly in the 90s, it is not a huge leap to assume that athleisure is popular because of its functionality.  
Fixtures of a society that are deemed “basic” are typically just popular elements of culture. And it does not end with clothes. Why do we feel the constant need to explain our attractions? Why can’t we take pride in our interests? 
There will always be a group of people that long to be “different” from the general population. They seek out stances that make them look interesting and cool. Disliking everything the mainstream likes is not to be free of mainstream culture: it is to build a personality by omission, by what you do not like.
That sounds exhausting, but if that is what makes you happy, by all means continue. People should do what makes them happy, and that extends to letting people enjoy the top 40 hits, Lululemon and pumpkin spice lattes.