Well for starters, it is not much a bother, since it is trivially easy.
If you have taken the time to stop by meta to read this, I imagine that you took a look at the questions on the main site first. Did you vote on any of those that you read?
Because we need more high reputation users.
As of today we don't have a single 10k user and we only have 9 users with a enough reputation to go to the close/reopen queues with the standard 3k reputation level.
Votes are signposts for those that come after you.
So voting is good karma. It helps to communicate your experience and knowledge to others. Even if it is just a tiny a bit at a time.
Why doesn't anybody vote, is Data Science Broken?
I do not think the site is broken, as other sites have faced the same challenge. A quick search finds many similar meta posts. So Data Science is traveling a familiar path.
4/10, 3/11, 4/12, 3/13, 8/13, 1/14, 1/14, 2/14, 8/14, 10/14, 8/15, 9/17
How can we change the situation?
Well, you can vote. Consider this a plea to spend a bit of your time voting whenever you stop by.
Besides, who wouldn't want to earn a nice shiny badge or two?