I think we're just going to have to agree to disagree. In my opinion posting the same thing across 11 subreddits (even as crossposts), pinging a bunch of other users, and making a lot of comments that mostly just said "move to lemmy" is excessive.
I'm not a mod of one of the subs so I can't explain why they did or didn't do something.
Again, I don't necessarily disagree with your motives but you made yourself a really easy target for reddit.
The user you linked made a single post and a single comment on the topic. You spread a ton of posts and comments across several subreddits.
The subreddit mods might have reported you to the admins as a spammer - that's what they do when they see someone breaking site wide rules. Like it or not, they are under no obligation to communicate with you about it beforehand. It's also possible that none of the subreddit mods had an issue with it and you happened to be noticed by an admin who saw you were breaking the rules.
It's not my opinion. It's literally in the site rules - https://support.reddithelp.com/hc/en-us/articles/360043504051 Bullet point 2 in the second list. Bullet point 3 arguably also applies since lemmy could be said to be unrelated to the subreddits in which you were posting. And when site wide rules get broken then it's the admins that step in, not subreddit moderators.
Edit: As for the self promo part I mentioned in my previous comment, that would fall under bullet point 2 of the first list in the link. While you may not actually have a stake in lemmy, your actions on reddit definitely made me suspicious that you did before I looked into lemmy more and learned who the the heads of the project are. It would have been easy for a mod or admin to have seem just your comments on reddit and assume the same thing.
I'm not saying I disagree with your motives but your actions were pretty clearly breaking long established rules.
There are plenty of other reasons to criticize reddit. Enforcing their existing rules is not one of them.
Ban evasion. OP literally said "Reddit has permanently suspended my account". That's just asking for it.
Yeah reddit sucks but this was a reasonable ban. I saw OP posting that all over the place and pinging devs to the point it looked suspiciously close to self promo. I'm surprised the ban didn't happen earlier. It was pretty blatantly spam.
I use old reddit on the desktop and reddit sync on android.
True. That should result in bans too.
I saw on reddit that OP got unbanned which does indeed make the situation a lot more suspicious.
In the end spam comes down to what a person thinks is reasonable and as we have seen time and time again, that definition varies from person to person.