I agree, it's a lot more fun to promote others' games that you think deserve attention.
Something to do instead of chasing ratings is to chase good games to rate.
It will give you insight into what others did great with the theme and their time in the jam and can therefore serve as a collection of inspiration for your future game jams, as well as contribute to the community.
Try to improve your own developing skills without getting too self-centered.
Game jams are all about community, so in my opinion, the best types of ratings and feedbacks are from those that found you through a sincere post in the community tab, a shoutout, or on their own game page when you rated it.
And in the worst case you won't get enough ratings, but what's the harm in that? I rather get insufficient high-quality ratings with great feedback than ass-kissers that rate my game low without playing it and begging me to play their game in the comments x)
I'm not provoked by someone doing this, just giving some examples and my two cents on this :)