The keyword in that sentence is trust. Either trust or check. Your choice.
Most people choose to trust certain software providers based on their reputation. But if you have serious doubts and you don't check, that would be your problem.
Whining about an open source project maybe being insecure basically means either check it or don't use it. Nobody is twisting your arm to risk your passwords on some wonky self hosted setup. Your problem if it blows up in your face. That's also what it spells out in a typical OSS license (that would be the section talking about limited liability). That's another thing people tend to not check that they probably should pay some attention to. Using the software means accepting that it's your responsibility.
If like most you are unable to make a sound judgment on this front; consider paying a service provider providing you a service. That would be Bitwarden in this case. They kindly provide a free version even. Easy choice IMHO.
Heart-bleed slipped through the cracks for a while and then certain software providers lived up to their reputation by providing fixes in a timely fashion. And certain others messed up by not doing that. I care more about how developers act when something like this happens than the fact that it happens.
OSS software providers are no different than other providers when it comes to trust. Except you have the option of looking at their code. Lots of people doing that builds trust. I tend to look at things like number of stars, commit frequency, and other things when deciding to use a random Github thing. When it comes to software that is safety critical, I prefer the scrutiny of an active community of developers. That just increases my level of trust.
IMHO Bitwarden's trustworthiness just went up by virtue of there being multiple implementations of the thing and apparently a growing community of users and developers depending on these things. I'm already using it and vastly prefer this over some closed source solution with opaque development processes. I probably would not self host but it is nice to have that option available.
