Koffee, he (she?) didn’t ask you for a psak. He/she asked for a discussion of the issues involved. Are there any other concerns besides the mixed seating? Does the conservative movement deny Torah min HaShamaim? that would make all of the “mispalellim” (for Joseph, note the quotation marks) kofrim which would be a good reason to avoid any association. Any other issues you can think of?
Edited for civility