Shanks could have easily stopped Yassop and the fact he showed no concern when Yassop was getting ready to shoot shows he was fine with it.
It's pretty messed up to play mind games with someone, let them go, then shoot them in the back when they start sailing away.
I don't hate Shanks it's just very out of character for him and it has made me like him less.
Yasopp had a point in doing what he did. Bartolomeo even found it weird that Shanks let him go, and if you read the chapter he clearly didn't learn his lesson. Yasopp was on business, even if a bit toxic. It's consistent with the writing we saw in chapter 1, the Red Hair pirates aren't saints.
But I don't understand why are you blaming Shanks for Yasopp's actions?
Did Luffy stop Zoro from kicking Loki? He did not. Do you blame Luffy for Zoro's actions?
Both the Straw Hats and Red Hair pirates are free people, doing what they want.
Nami said that he doesn't want to leave the kids behind at Punk Hazard, and Luffy followed Nami's demands. Law was surprised that Luffy is giving so much decision making to Nami when she is not even the captain.
Shanks let Yasopp make his own decision. If you want to blame someone, blame Yasopp.