Let's put it another way, if the average starting pay for an engineer is say, $2.4K and you see an ad for people to do ad-hoc engineering job which involves perhaps 2 weeks of work that any other engineer would do, and the ad offers to pay $80-$120 for opportunities and additions to your engineering work portfolio, would you say the same thing? Anyways, it is still a free market, if there are willing takers for the job then good for the TS. Nonetheless I guess the on-lookers can always share their opinions and views and give feedback, and TS always has the right to take their feedback or not.
Let me start off by saying that I don't think anyone should spout the phrase "pay peanuts you get monkeys".. For one, sometimes the people offering the jobs really don't know and just want to get the photographs (more often than not this is not true though) within their limited budget. Also, it is not impossible to find a decent photographer for a cheap price. After all, the converse isn't true either, just because you throw diamonds in the air doesn't mean you get the cream of the crop. Some professional photographers who aren't that great *can* BS clients who don't know better and command a high fee for the standard of work they do (it works both ways).
Nonetheless, I always advise friends who dabble in photography jobs to supplement their income to think of the real professionals. Not that these professionals need mollycoddling, but you are literally spoiling the market if you accept jobs well below market rate. I guess when professional photographers complain and make snide remarks about such ongoings, it is in some sense, similar to the numerous complaints that we often see online about foreign workers competing in the job market and accepting lower pay. And that's not even the same thing, since the foreign workers still have a minimum wage requirement, since it is their primary source of income.
There is also some form of exploitation going on (whether the people offering the jobs know it or not) when people are being charged way below market rate for their photographs. I guess sometimes hobbyists get so carried away with the promise of "addition to portfolio" and "chance to be published and credited" that you fail to examine how much value the additions to your portfolio and how much coverage you'd get from the publications promising fame and fortune in question. Hope this explains where I'm coming from. Cheers.