...because we like monero, consider the technology more appropriate and mature for the task, and wish to use it. Currency abhors liquidity barriers, slippage, etc. Since Monero is the most liquid crypto that provides acceptable privacy and hence fungibility, it is a win-win situation if it is universally adopted.

Also the corrupt terms of the zcash social contract make it abhorrent to many of us, who believe in open source, peer-review, and decentralization of authority, as well as casting deep suspicion on the motivations of the beneficiaries of zcash's corporate structure, and the acts which self-interest will therefore dictate.