Gambling is not TOS violation. Exposing CFs IPs to be blocked would affect ALL customers so CF is naturally aggressively protecting those Running any business that puts CFs IPs at risk is the TOS violation here.
I wish I was the fly on the wall during that meeting, but I have very little doubts casino understood the problem very well and were trying to weasel their way out of paying for an enterprise service (to anyone) and having to use their own IPs which are trivial to block. And if you continue buying more and rotating it will likely quickly get you on the black list with anyone still selling them.
I may be simplifying and maybe casino's CTO and the entire tech team are a bunch of naive newborns, but I really fucking doubt it.