I looked up the Open Technology Fund on Wikipedia and it has no relation to the CIA. well, except that its parent agency (Radio Free Asia) is part of the US government like the CIA is. they don’t seem to work together at all, and they’re under the purview of two different branches of government
besides, as other commenters have said, they’re open source and they’ve been audited. anyone can build the client themselves (with any potential backdoors removed) and set up their own server. would the CIA allow for that?
Different people don’t like it for different reasons. Some people don’t like it because they think it has CIA financial backing (nope), and some people don’t like it because it requires your phone number, therefore it is not private (the privacy it provides is more than sufficient for anyone not actively being persecuted by a Five Eyes state), and some people don’t like it because it feels corporate (it’s a 501c3 nonprofit, and how corporate it feels is subjective).