They even cited that the charge was for "mining fees." Are you kidding me? Mining fees for USDT. In short, I rushed to the live support, and we had a very heated argument that later made them apologize.
Exchanges generate revenue mainly from two things, one is trading fee and the other one is withdrawal fee so paying $8 fee is insane but that is the cost for the service, I am not backing the high withdrawal fee here just presenting the facts. Good thing is most exchanges will have flat fee so it's same if you withdraw $10 or $1M so retail users need to be careful when picking their trading platforms.
One possible way to avoid these huge fee is pick the platforms where LN withdrawals are available for BTC, ofcourse you need LN channel and need to pay fee to close the channel to move it to on chain but still it will be cheaper than paying $8. Once you moved to on chain you can exchange BTC to USDT on here forum or if youre lucky you may find to use LN itself.