Um...actually, sending a thank you note is expected after a callback...
no, it really isn't. i've spoken to partners and recruiting people who said thank yous almost invariably hurt the applicant and never help. but thanks for teaching me about the application process, 1L.
and fwiw, i didn't send any thank yous and received offers.
first, im not a 1L. second, i have an offer at a very highly ranked firm. third, the only way they hurt is if you can't write "thank you" without a typo. the issue is that there is no correlation, not that they aren't necessary.
next time you call someone out for being an ill-informed 1L, take a look in the mirror and realize why no one likes you. enjoy your summer being the SA no one talks to.