I've yet to experience OP's anecdote but I've had analogous experiences with employers. I don't do the HN threads so this is all from my Github with considerable side project activity albeit nothing serious; I don't even have the stars to show for it. Their template is

"Dear <name derived from GH profile>,

I've seen your recent activity on <project which does indeed have a lot of recent activity> and it has caught my interest. I am a bigwig at a company specializing on developer-experience for the Go toolchain..."

It's all downhill from there. At that point, I would either realize that, hey, the project you mentioned doesn't use Go. Heck I don't use Go. Or, if the second sentence was still relevant, the next few sentences is nothing but either a thinly-veiled attempt to make me use their product or answer a survey. I really wouldn't have been opposed to this if only it was actually relevant to me; unfortunately I don't think you can come up with a boolean search query that better qualifies your leads.

Ten-ish years ago when I got cold emails because of my GH activity, it was at least a lot more relevant to me.

As OP said, it's not really a big deal but it compounds. My worse was three such spam in a week and it made me contemplate taking the project private.