Regardless of your claim that it's not an amount that means anything to you, I still wouldn't waste money so easily without first checking who I'm sending the money to. Considering that you have been involved in all this for more than 10 years, I am surprised that you have put yourself in such a situation - although if you were to repeat the same thing with any CEX, each of them would ask you to prove the origin of the funds, because for most of them it is still a significant amount of money.

Technically speaking, they are not the ones to blame, because it is up to you to prove where the $100k came from.