Perhaps social media has had an impact, but IMO the larger issue at hand is that people (especially in the US) have both less time and fewer places to have casual conversations. People are working more across the board and have more distractions and things vying for their attention (mostly because of the internet and social media, ofc), so even when a situation appears, there is a higher cost to interact, whether that’s in real life or on the internet.
Fwiw, direct messages can be a swamp of nonsense, especially for people who post a lot publicly on social media platforms. They may not be intentionally ignoring you, but you get lost in the mess. Women especially get harassed via DM on basically every platform so there is a tendency to ignore DM functionality. Platforms that are already set up to facilitate random chats like forums, discord, etc are going to be way better for having a real conversation that could even become a friendship
Some people aren’t a fan of F-droid managing the signing keys and that sometimes F-droid builds/deployments can take a bit. There is an argument for developer-managed signing keys being better than registry-managed signing keys for trust, but that also doesn’t make F-droid “bad”. While I’m not fully versed on it, I think the issue here only applies to the main F-droid repo since other repos might have different policies around builds and signing keys.
Personally, I like the experience of managing my most used apps through Obtanium via the devs git releases, but I only use that if the dev is good about publishing their signing key so it can be verified with AppVerifier. Otherwise, F-droid is safer than running an app installed without verifying the signing key.