Seems like the reason he can't block people is because it prevents them from replying to his posts and engaging in the public conversation. Title seems a bit misleading, almost makes it sound like he has to read all of his twitter replies.
On a tangent, what is the deal with the "Drumpf" thing? It was his family name some time ago, so is this just the other sides' "Barack Hussein Obama" or is there more to it?
No, it's not the same thing. The Hussein thing is that the Alt-Right uses it to imply Obama being a Muslim (which he is not) and thus, by extension, a terrorist supporter/enabler.
The Drumpf thing, however, is nothing more than highlighting the family origin (which Trump actually even stated himself, per https://www.snopes.com/fact-check/donald-drumpf/).
It is from HBO's Last Week Tonight. The joke is that Trump made fun of Jon Stewart for changing his last name in a tweet [1], which is silly because his family did the same.
>I promise you that I'm much smarter than Jonathan Leibowitz - I mean Jon Stewart @TheDailyShow. Who, by the way, is totally overrated.
[1] https://twitter.com/realDonaldTrump/status/32707672042545152...
That is something fundamentally different, but Last Week Tonight is just some comedy show, so one should not expect too much here.