Make a statement, this fake culture is the enabler for SLT's bullsh-t. It's the tool they use to manipulate the masses!
Fight back, wear normal cloths to the office. The layoff list is already in motion and your T-shirt choice isn't going to change anything at this point. However, an office without Magenta gear will send a strong message and will undermine their power.
Own your identity, take SLT's away and may the odd's be ever in your favor.