Ahem... I hate to break it to you... 10 isn't even the limit of allowable tags, it is just what Steempeak set their own limit at.  I am not sure if the blockchain actually sets a limit, but if there is a limit, it is REALLY large - see e.g. https://steemit.com/revolution/@netuoso/jfk-secret-societies-1510793787

But back to the actual point at hand, I totally agree with you that if there isn't at least one relevant, popular tag to the post e.g. #art or #photography or whatever is appropriate, than something is wrong.   And using tribe tags that *aren't* relevant is actually straight up harmful and likely to get you muted from the tribe's front end and your rewards flagged away anyway... so... why do it :)