The usual way of managing those when politicians and the public notice them is to restrict borrowing. (Yes, these metrics are calculated, the complaint should be "listen up, heathen, this is what you should be heeding--listen to me!"
Then people don't like effect that this change has on the system that's being regulated. Who knew cause and affect was a thing?
We know about second-job holders, too. Sometimes you have to watch for the agitprop to get to complete data, though. But the BLS also has this data.
Both are measured. Not everything that's measured gets managed.
Take https://www.census.gov/library/stories/2019/06/about-thirteen-million-united-states-workers-have-more-than-one-job.html as an example. It has a lot of numbers and charts, and I'm betting most people will take away all the wrong information. It's hard to sift through the implied claims--women are much more likely to hold a second job (it's a very small percentage difference) or the assumption that we're talking about full-time + part-time work when at least some of the skew is because women have two part-time jobs. And yet, it's a small percentage.
It's hard to reconcile that article's numbers with https://www.bls.gov/opub/ted/2018/4-point-9-percent-of-workers-held-more-than-one-job-at-the-same-time-in-2017.htm?view_full even though they claim to use the exact same data source. Of course, I'm not comparing 2017 with 2013, the "4.9%" source also includes 2013 data in the graph, at odds with the "13 million" article. I could say that there's a 25% difference between the two articles for multiple-job holders in 2013, but it amounts to maybe 2.5% of the workforce. What's most dissatisfying about the "13 million" article is the trend shown in the second article: That this group has been on a steady decline since the mid '90s. It's only a huge political issue now because it's a political issue; it's less of an economic issue now.
It's also worth noting that second jobs have many reasons. I've worked two part-time jobs to get experience in one job and transition to full-time work (turning down full time work at one job), or because I could only find two part-time jobs and needed money for food and rent. I've freelanced on the side because it was fun or because there was a specific need--a specific bill or a specific want. For a while my wife and I both had part-time jobs so we could send money to help her mother out of an IRS problem. My father worked two jobs for a year because he believed his industry was heading for a really nasty strike and I was in gestation, so when the strike came and 30k men went looking for jobs, he already had one to tide him and his family over.
I lean towards the second article's statements. Why? Because it has the balls to refer directly back to the actual data from BLS, and to the extent I checked, the data cited in the "4.9%" article are the BLS data.