Is it better to reply to toxic people in the same manner as them (to teach them a lesson), OR just not reply to what they're saying?

You can't change them, so in the end, saying nothing or being snotty back to them accomplishes the same thing - nothing. I will often leave the toxic people alone and spend effort on the nice ones. Sometimes though, it's just fun to out-toxic their comments and see who else piles on. Just for fun, since there's zero chance you can get them to think "gee, I've been an a-hole. I'll apologize and be nice".

In general? Just move on. It's not worth it.

Mark Twain is quoted as saying...."Never argue with a stupid person. At some point they will bring you down to their level and beat you with experience."

Toxic people want you to match their toxicity

My nemesis is an autistic German guy
whose rudeness is beyond as are his expletives. He lives around the religious sites. I just avoid them.

Toxic people rarely realise their toxicity.
To fall to their level means adding to the whole toxic level.
I would just rise above it. Walk away from it if possible.

Engaging toxic people on their level us a mistake. You just end up frustrated and angry.

Actually, I do that to people most all the time...it's passive aggressive

Since people are inheritenly a little to very dumb...it goes well over their heads

Latter. Negative energy acumulates.

NEVER lower yourself to their level,,,,,,,,,,,,,,,,,Laugh in their face & walk away