The preference of GIS Moderators for users to consider commenting, editing and/or downvoting, rather than flagging as low quality, for anything but the lowest quality posts is long standing. For example see this answer by @underdark to Why was Very Low Quality flag declined?
I think it is line with this answer to The limits to a Very Low Quality answer at Meta SE.
The way I assess Very Low Quality flags is to see whether:
- the poster has attempted to answer or ask a question and just done so poorly. If so, I think this is a low quality post and should be addressed using a comment, edit and/or downvote. I decline such flags.
- the poster has not attempted to answer or ask a question and has instead posted something akin to jibberish. This is Very Low Quality and I mark such flags as Helpful.
I did not see the particular flag you have asked about until you asked here but I can see that one other user has commented on it (automatically via the review queue), no one has edited it and no one has downvoted it. The answer you flagged looks like a genuine attempt to answer. Consequently, if that Very Low Quality flag reached me then I would have declined it.