The "Jet fuel can't melt steel beams argument

I like to browse a lot of forums, sites like 9gag with some stupid or funny shit, maybe some imageboards to kill time.

Scanning the comment sections of various websites, I tend to notice someone touching the subject of 9/11 suggesting, that it might be an inside job, there is always someone who replies with
"Jet fuel can't melt steel beams". This meme/trend grew to the scale so large, that it started to live its own life as a meme. So whenever some blindfolded cattle disagrees with someone with a strong opinion about ANYTHING (not necessarily 9/11 events), he uses "Jet fuel can't melt steel beams" line with a heavy, sarcastic and mocking tone to it, implying that the other guy is a nutjob conspiracy theorist.

The fact that jet fuel burns in temperatures too low to melt steel becomes irrelevant. Because anyone who reads the discussion - someone who didn't look into the subject of 9/11, people with a very vulnerable minds, and mostly teenagers still developing their thoughts about this world - will take the side of the mocker, mainly because of how much more elaborate (or even cool) his response seems to appear in opposite to the other side of the debate. (sarcasm seems to indicate intelligence these days). In other words, this lead to people discrediting other people with the actual FACT , which in the eyes of average person becomes BS, because of the way it was presented. And by the amount of upvotes/likes/etc. these comments get it seems like people choose not to think by themselves.

I don't know why, but for me it seems fishy. I cant help to think that this "meme" was somehow manufactured by the people who want us to forget. An example of mass manipulation. Yet another way to hide the truth.