I don't get it. Is Counterparty forbidden, or does Bittrex have personal issues with Counterparty developers..? Are they going to delist all Counterparty tokens they have on their exchange, and why would they do it? I understand Counterparty and Omni are a bit out of fashion at the moment, but delisting a token because it is based on a non-fashionable (but still perfectly valid and viable) technology, is pure nonsense. I suppose there may be misunderstanding there.
I believe it is the combination of being an XCP token and low volume; if I understood correctly there is some overhead for exchanges (or maybe just Bittrex) when it comes to XCP and its tokens, which would normally be covered by fees gained from trading volume.
I notice they are only charging 5 DTB for a withdrawal.