Yes, you can flag these post because they are just re-posting what others have already said and not posting meaningful content. Every post must be on-topic, meaningful and not a duplicate of what others have already said:
(Official Rules of the Roblox Developer Forum)
If I can remember correctly I messaged the DevEngagementTeam asking about a similar issue with generic support posts in announcement threads and they said you are right to flag these sorts of posts.
I would urge anyone replying to announcement threads to use the like feature instead of replying with generic spammy replies so that the useful discussion doesn’t get drowned out.