Huh? What I see from looking at sites that actually show quantitative data about labor market outcomes for different majors is quite different from what your generic anti-social-sciences sneering suggests.
In that list, the highest unemployment rate is for Physics majors (7.7%). The majors of Psychology (3.9%), Communications (3.6%), and Liberal Arts (4.3%; I don’t see a listing specifically for Gender Studies, possibly reflecting the fact that at many institutions it’s an academic minor but not a major) all have lower unemployment rates than Physics, Computer Science (5.2%), Mathematics (4.9%), and General Engineering (4.9%).
If we’re looking only at underemployment rates, fields like Liberal Arts (59.5%), Communications (54.1%), and Psychology (50.0%) rank higher, but so do fields like Criminal Justice (73.2%), Business Management (58.8%), Agriculture (58.7%), and General Business (55.0%).
Even many of what you would probably assume to be more intrinsically “useful” academic fields also have substantial underemployment rates, including Biology (46.1%), Engineering Technologies (40.4%), Economics (39.5%), and Chemistry (37.9%). If nearly 6 in 10 Liberal Arts majors are considered “underemployed”, but so are nearly 4 in 10 Chemistry majors, is that difference really indicating something so terribly significant about the relative social value of those fields?
All of which goes to show us that the sort of knee-jerk disdain for “non-STEM” fields routinely indulged in by the old farts who run conservative media outlets is not necessarily a reliable guide to the realities of the labor market.
Another reality of the labor market that anti-education conservatives tend to ignore is the fact that female-dominated fields tend to be paid less, not because their jobs are less “valuable”, but because their workers are women.
If you look at the “Median Wage Mid-Career” category in my previous link, you’ll see that the lowest slots are solidly dominated by various areas of Education. Is that because educating children isn’t actually a valuable activity for society? Horseshit: it’s because educating children is traditionally (since the early 20th century, at least) considered a woman’s job, and employers tend to take it for granted that they can and should pay “women’s jobs” less.
The “plumbers and carpenters” of your example, on the other hand, are fields still overwhelmingly dominated by men, which may help explain why society thinks they deserve to earn good money even with no college degree. (Not that I’m arguing that plumbers and carpenters, whether male or female, shouldn’t make good money, or that college ought to be required for all or even most jobs. I’m just calling bullshit on your naive assumption that pay rates are automatically a reliable measure of the social value of a profession.)
So yeah, we need to take labor market outcomes with a few grains of salt when considering what pay and employment levels really say about the true social value of fields of study. As for the sort of half-assed anti-academic prejudices that you’re describing, we’ll need to head to the supermarket and stock up considerably on salt.