The band. You should blame the band. The band has the ultimate authority.

If the band said "refund everyone who wants it or we won't play" that's what would happen.

If the band said "don't you dare refund anyone, we're the headliner and we're playing" that's what would happen.

But everyone who already has a ticket, by almost definition, loves the band, so are all to happy to blame everyone else except the sexual predator who wants to keep your money.