You are the last word if we want to have a productive internet discussion
But I do not think the goal of such nuclear discussions on the internet is productivity, instead it is all about emotions and spite. It is about feeling good about yourself and your identity.
If you are not organizing, or making policy discussions yourself it is just mental masturbation.
Now it is sometimes good to mentally masturbate in order to do many things such as 1) stress relief, 2) to understand an issue in a better more nuanced light, but there are also other reasons such as 3) pride, contempt, yadda yadda yadda and so on where you just want to feel alive.
-----
After all taking joy on having the last word is not really about having the last word but instead a form of schadenfreude about winning.