He seems to have very messy relationships with women with whom he also collaborates, he went on Alex Jones' podcast to compare "SJWs" (lol) to the KKK, and apparently he threw a bunch of guitars at his guitar tech (who went on to join A Perfect Circle) while at Lollapalooza.

Finally, he sacked the drummer for suffering a heroin overdose between Melon Collie and Adore and they changed their sound to more electronic, and a lot of fans saw that as him trying to change the Pumpkins into a solo act, and responding by calling anything after Adore a "tribute act" and claiming that the real Pumpkins are Iha, Chamberlain and Wretzky, and Corgan is just a side member.

He just kinda went crazy.

That, or he always was.

Like the other comments said. For my part, I saw him live in 2010 and that was enough for me.