"This is something that really irks me about online discussions; we're not having a formal debate here, not passing policies, we're having an informal conversation about jobs."<p>Sure.  But if someone makes an interesting claim, especially one that contradicts their own experience, knowledge, or intuition, they'll likely want to know if you know something they don't.  So, people like me ask for more information, specifically concrete data.  If I find out it's just a gut feeling,  or  a guess, or whatever, that's fine by me.  But I just want to know.<p>"I gave an opinion and stated it as such...yet my opinion isn't valid because I don't have research data to back it up?"<p>Maybe.<p>Not all opinions are valid.  Sure, you're entitled to believe what you want, but if you make it public then expect others to ask questions, and absent any evidence or a good argument, to scoff.