pretentious, adj. Attempting to impress by affecting greater importance, talent, culture, etc., than is actually possessed
Learning latex because you're curious is one thing. Using latex on your resume solely to give the impression you know latex would qualify as "affecting greater talent than is actually possessed".
I don't think that many people use LaTeX on their resume as a way to look impressive just because they know LaTeX. I think that many people use it because they find that it easier to control the layout of their document than in something like MS Word or {Libre,Open}Office Writer. I spent a number of years with a MS Word resume filled with tables to space things out correctly. I used to dread needing to make changes to it because of how fragile the setup was. On the other hand, I find it relatively easy to make changes to my resume now that I have it in LaTeX.
I don't create many documents in PDF or print form. When I do, I use my very basic LaTeX knowledge to create something that looks nice. Because word processors are useless and fiddly.
It's cynical and utterly baseless to deduce "pretentious" motives.
I think most people who use LaTeX on their resume would do it because it makes it look better and is easier in some ways (that McGee mentioned), not because it is there to pad their resume.
McGee explicitly mentions that the reason he does it in LaTeX is not to get the "+12 points bonus". I think you're being presumptuous in accusing others of being pretentious for using LaTeX.
