People here’s take about why free software (“open source”) should be preferred, in my opinion (basically the OpenBSD’s opinion) is flawed.
You said “open source” is “good” because it permits having eyes on (“auditing”) and make sure there isn’t malware.
This is NOT the most important benefit. But it is flawed because, you guys don’t even have the knowledge to do coding. You guys are activist/“journalists” working for CIA. So you cannot audit the software yourselves.
Or “open source” but with a bad code style, how can you make sure the code doesn’t have backdoors? But I think hilarious journalists that is only smart enough to post fake news about how down is the Russia and China economy can’t even write bad code.
“open source” is good, firstly, because it permits auditing the source code and find the bugs, replace flawed/bad code with safer alternative (for example, the advantage of an open-source C software when porting to OpenBSD is they can replace every occurrence of strcat/strcpy with safer strlcat/strlcpy), sandbox it (on OpenBSD, with pledge and unveil), do privileges separation and revocation, etc.
And I think “you can make sure there isn’t malware/backdoors” is the second benefit, NEVER THE FIRST.
Conclusion: Do not blindly trust what is “open source” when you can’t even do code auditing.
I saw the clients are open source, but what about the server??
Anyways, if you put your data on others’ hard drive, NOTHING will guarantee the data can be erased on demand.
But well, when the clients is open source, PGP-encrypted messages are mostly safe.
Except if you get the key from their web client.