I do. It's frankly selfish. Having an AI get training on my old comments costs me nothing and it results in the development of useful AI tools. Trying to sabotage that is petty and pointless. It's not like you could somehow collect the fraction of a pittance that you think you're owed retroactively. I never commented on Reddit thinking "awesome, I'm going to make bank on the content I'm generating here."
People complain about the capitalist mindset of the world and then they do this. Sigh.