I would say if you think you can tell someone is acting in bad faith. Call them out on that and explain clearly why it's bad faith. You can just ignore any response after that but I think it's extremely helpful to future readers if you can make them more aware of the tactics people making bad faith arguments use.

As op said. If you don't have the energy or desire to make a response it's more than ok to not engage of course. I would not want to wish arguing with people online against your will on my worst enemy.