Weird "Linked-In" recruiting emails

I often get emails saying something like "Hey, I'm SOMEONE from REPUTABLE COMPANY. I saw your profile on Linked-In and we'd like to know if you are interested in POSITION with us." Yesterday's email was for "Senior Python Developer".

I reply to these saying how I already have a job, but that I deleted my Linked-In profile a year or two ago and that I'd appreciate it if they could tell me where they got my contact information. The resultant emails include backpedaling and claiming that they must have seen a forum post by me, my (non-existent) github profile, or something. Consistently. The initial email always states Linked-In. But follow up inquiry by me results in hand-waving.

The emails always come from some HR person at a reputable company. I'd love to know what is going on. Is Linked-In selling my old information (even though I believe I deleted my account) as part of a database? Is there some lead harvesting service that collects this information and sells it?