The strongswan installation itself doesn’t seem to be malicous.

It looks like these packages were installed via the apt repositories: strongswan-starter
strongswan-libcharon
strongswan-charon
libstrongswan

It definitely is worth it. In terms of the number of users, it certainly cannot be compared with Twitter. Measured in terms of interaction, meaningful exchange and a nice community, it is worlds better than Twitter.

There are topic-oriented instances, e.g. for cybersecurity (https://infosec.exchange/). But of course you can follow people from other instances through the federation. The advantage of topic-oriented instances is that you have a local timeline on which all posts of your instance appear.