Speaking as someone who left academia close to two decades ago, sama hit the nail on the head.

The kinds of people that sama is targeting are ones who in the current system are going to wind up in postdocs or teaching adjuncts. With the way that universities are structured, all incentives are to have as many of these as possible doing teaching, pay them as little as possible, string them along on as long as possible, and reward as few as possible with the golden apple of tenure. These incentives have been taken to an outrageous extent. If you are a young researcher and are concerned that YCR is too risky, then you're not being honest about your own prospects.

Increased funding for research does not solve this problem. The university system structurally creates more PhDs than it can create jobs for unless the university system is growing rapidly. This was last true in the 1950s and 1960s, but has not worked out for most grad students since. Shrinking is admittedly worse than steady, but both are bad.

Therefore the YCR opportunity gives researchers a chance to do research that might or might not be better than a regular postdoc, and significantly improved job prospects if it doesn't. The best way to address that issue is to be honest about it.