People were getting justifiably pissed off about what felt like a complete "whim" decision to defederate mastodon.social.
Not realizing that no one was announcing defederation, but a Silence. (Also known as a "Limit")
Silence is infinitely less destructive, and doesn't break follow relationships, and still allows you to follow people on the other server, it just puts the server in a more 'restricted' mode so that randos from that server don't have the same privileges (to your eyeballs) that non-silenced servers do.
Suspend is what you do when you're done with that server. When you've given up, and when you've informed users on your server that you're defederating a server that has existing follow relationships you're about to break.
Most of the time that is not a decision that is made lightly especially when there are already existing follow relationships between the two servers.
(This is another reason mastodon.social has little to fear from defederation, but I digress.)