Surely two things are important..
(1) To be able to live, ideally comfortably
(2) To be able to do / achieve what you want.
I spent much time as an Engineering student / recent graduate working on a couple of charity/educational design programmes - it gained me a lot of experience that eventually got me the job I really wanted (bottom of the ladder in an FT department) - it got an educational charity a trained graduate engineer they wouldn't have had either.
I do a certain number of annual inspections and air tests on local private aircraft free because I can, enjoy it, and other people benefit; I'm even preparing a performance manual for a homebuilt for somebody for free, since it would otherwise cost the owner a substantial percentage of the value of his aeroplane. I don't see any more problem with that than Rich's seminars and free training, and anyway haven't the time to do enough to significantly effect anybody else's income.
The bottom line is that at any time the number of qualified pilots or engineers who can/will work for free are very few. So, it's never really going to affect the state of the industry much, but may in some circumstances allow a worthy cause to get something they couldn't otherwise afford, or a beginner the experience they need to start being able to live off it. I have no problem with that.
G