Or, they’ll be like the OP and just ignore a new coworker entirely and never even say hello, which is also kinda rude and makes people think you’re mad all the time.
Same. Outside from a quick hello (and I mean quick) to people I've deemed friendly, I'll only talk if the job I'm doing demands it. I won't be rude if someone asks me something, but the answer will also be quick and to the point.
Not engaging with someone for two weeks isn't not being good at smalltalk. It's actively ignoring new coworkers to make yourself feel better. Which is selfish behavior
On the contrary, being so entitled that you think you deserve other peoples' initiation is selfish. You might have the impulse to spout to other people, but a lot of people don't, and they just do their job. Why isn't the other coworker rude for not making small talk for 2 weeks? Why isn't it that the other coworker is only making "small talk" to (insulting) someone else to make themselves feel better?