7.2 talks about images and audio-visual content.
Submitted text shown in an extension is neither of these things*
UNLESS * it’s shown on stream via an Browser Source.
In My opinion: everything should be user moderatorable and ran past the auto mod API endpoint first before accepted for submission. So you should provide the ability for moderators (and above) to remove user submitted content, irrespective of this rule.
Automod Endpoint:
You don’t want someone to put “follow my channel < link >” for example and have no way to easily remove that.
I think the intent of this rule is to protect what appears on stream/recorded to video as apposed to what is sent to and shown in the same extension. But you should still provide the tooling.
Disclaimer: not Staff or review team, this is all my interpretation and how I’ve implemented the rules. Given most of mine don’t use user submitted content. And where they do the content in question existed prior to the rules and is moderated before it’s live.
See also, these uservoices for making it easier to moderate such content
Summary: the use case you describe should be ok, but you still need the power to moderate the content in the extension in case someone tries to submit something they shouldn’t or violates the channel rules that the channel installing the extension has.