People on Lemmy can be a bit rude at times, but it’s not like they’re actually toxic. A huge proportion of Lemmy (and mastodon) users have tech background, and this demographic are often very direct and don’t mince their words when posting online, which can appear to be rude and unwelcoming. Just keep your head cool when talking to them.
That being said, toxic people do exist here though, the kind of people that downvotes and do personal attacks when people post something they don’t like instead of doing civilized discussion like normal people. Most people here probably know who I’m talking about lol.