I can't say I've ever experienced this. In fact, I would occasionally browse r/T_D just to temper the overtly left-leaning bias of /r/news and /r/politics.
/r/politics is only left-leaning because of how heavily skewed right american politics is. Most of their opinions are centrist at best. Their obsession with trump is a bit annoying, but it's only annoying, not actively harmful.