blow smoke : to speak idly, misleadingly, or boastfully
Who knows? Were you accusing the people you evoke of speaking without due consideration, or of speaking with intent to mislead? Who knows? Maybe you were accusing them of inhaling cocaine ...
I think you mean
snorting blow, not
blowing smoke in that particular instance.
Anywaaay, I think I can see the distinction that you are making. But stating that
those who claim (x) about the effect of gun control measures on crime rates are "blowing smoke" (Slackmaster) and stating that
the evidence for (x) is not available (the news article) still seem to amount to pretty much the same thing...