Toxic is a general term for 'detrimental behavior towards others'. Its actual meaning varies based on context, and it's usually not that hard to figure out if you have a base understanding of common sense.

If you get called 'toxic' on a regular basis, then maybe it's time to re-evaluate how you interract with others or, at the very least, not make a sport out of antagonizing people who's opinions vastly differ from your own.