Responding to messages from recruiters

I respond to anyone who put genuine effort into reaching out. A lot of people use chatGPT or some copy paste thing they send to 100 people. If someone treats you with respect I would suggest reciprocating that.

Tho its not rude at all if you do decide to not respond. No one is obligated to respond

Doesnt have to be long. a "hey thanks for reaching but im not looking at the moment" is sufficient

You're certainly not obligated to reply to everyone (or anyone!).

Candidates who get ghosted by companies usually feel frustrated because they spent a few hours interviewing and then got ghosted. If you've previously engaged with the recruiter, I'd close the thread politely.

But if you have no relation to the person messaging you, I wouldn't waste time with a reply unless (1) it's clear they looked at your profile (2) it's a compelling offer or (3) you can truly help them without a huge cost for you.

My philosophy on engaging with random recruiters: https://www.jointaro.com/question/PFaieNRgMH1vgIsQjPn8/how-to-manage-recruiters-on-linkedin/

I think I have a different definition of ghosting than you do: I consider it ghosting when a conversation has already been initiated and 1 party just cuts it off. As you mentioned, the classic ghosting is when you go through hours of interviews just to have the recruiter/hiring manager go radio silent (this is what happened to me after my Google onsite in 2015 RIP).

Given that you're a FAANG engineer, you're definitely going to get a lot of low-quality messages, especially on LinkedIn. Your time is incredibly valuable, so you shouldn't feel obligated at all to respond to them. Lowball offers are particularly insulting as I'm sure you're well-paid at Apple ($230/share, $3.5T market cap, congrats!), and the people making those offers frankly don't deserve to even be told the time of day.