In my very limited, non-dev view of ActivityPub, it seems as though there's nothing that devs can do that would be a "violation of the spec".
With the way that a lot of implementations only use certain parts of the spec, fragmenting the Fediverse into seperate spaces in which only uses of the same software are compatible with each other; it leaves a lot to be desired...
What can devs do "wrong" that would make them seem malicious in the space?
I would have thought complete interoperability would be a major feature, yet I have been infinitely disappointed with current implementations and their almost complete incompatibility with other implementations.
Lemmy and Mastodon being one of the most notable examples. You can post to Lemmy from Mastodon and it seems to work pretty well for the most part. Yet posts from Lemmy on Mastodon, outside of strictly plain text comments, are literally just a link. From what I understand this is due to Mastodon not accepting "article" content types, which is what Lemmy uses for "posts".
@BeAware complete interoperability would indeed be a wonderful feature, but the simple adage holds true: the first 90% takes 10% of the time, the remaining 10% takes 90% of the time, and is also not very fun to do 😁
Also, what does "complete interoperability" mean when different software do different things? Anything that is a superset of #ActivityPub is easy (e.g. upvotes/downvotes are a superset of AP Likes), but its very hard the other way (#nodebb doesn't do post visibility like Mastodon)
@BeAware@devnull thing is: they didn't ignore it, they support it by displaying objects of this type as a link to original instance.
I do think they should just display the content since all this results in is note abuse (this is how wordpress does it - by just not actually actually the type meant for the exact kind of content they're publishing just because Mastodon decided they don't want to display it properly), but they still do technically support all object types.