This kind of exploitation is as old as mankind.
OldGeekJobs.com works since it's the reverse of this... essentially discriminating against younger candidates. It's not legal to discriminate against 40+ in the US.
[0]: https://www.dol.gov/general/topic/discrimination/agedisc
A real issue is targeting jobs for people who don't live in places that are known tech hubs. It took me knowing the right person to finally get a 'real job' in the field, and I only got it a few months ago (less than 2) I honestly don't know what I could of done otherwise, I've applied at a number of places and only ever got maybe one email back.
This is why code schools are so successful, unlike a traditional educational institute they are usually run by people who have worked in the industry, who will have the contacts to get you your first job.