People who have careers in tech are likely to read an internet forum whose readership is directed at people who have careers in tech. So we aren't going to get much "people who don't have careers in tech" side of the story.

Hypothetical example: Say only 1% of coding bootcamp graduates find the program to be a "success" for them. All of that 1% read hacker news and zero of the 99% read hacker news. If you ask about bootcamp on hacker news you'll only get HN reader's perspective, then you'd believe bootcamps are wildly successful whereas the real number is the opposite.

All that matters is if P(reads HN | works on IT | completed a bootcamp) is different from P(reads HN | doesn't work on IT | completed a bootcamp).

If they are different, one can not make statistics out of the comments here.