The "hosting terrorists" part would be referring to the Houthi soldier he interviewed on stream. I personally don't have a problem with having controversial people on for stuff like interviews but the problem was more that Hasan was trying to make him seem more appealing and only giving him soft-balls.

The Houthi guy was talking about guarding captured foreign merchant ship crews and making them dance and Hasan was talking about how much fun that must have been.
Hasan later cut him off and redirected when he started talking about how the knife on the shelf behind him can't be sheathed until tasting blood.
Hasan ran out of prepared questions pretty quickly so he started asking him about what his favorite anime was and what fast food they had available there. He was just generally trying to make him seem relatable.
Someone in chat wanted Hasan to ask about if they would release the hostages if peace or a ceasefire was negotiated and Hasan something like "I'm not asking him that, of course he would".
He later described it as "like talking to Anne Frank".

The "blasting propaganda music" refers to him showing a Yemeni propaganda music video on stream to a guest and viewers. The lyrics were mainly about all the weapons and war supplies they wanted, and what they would use them for. It honestly was just bizarre and left everyone confused since there wasn't really context for showing it.

I love how people (rightfully) called out Pewdiepie for jokingly paying guys to put "death to jews" on a sign, but when hasan does it unironically its okay

Not sure if the "Death to Jews" thing is referring to something specific or just that Hamas is very vocally anti-Israel.