[Tokhtamish]

Of course it is.

There is a Monty Python sketch about someone going into a restaurant to order breakfast. No matter what he orders, part of the order is "Spam, spam, spam, spam, spam, spam...". He argues that he doesn't like Spam. The waitress tries to placate him by offering him "Spam, spam, and spam. That's only got a little Spam in it."

Early geek culture revolved around things like Monty Python, Star Trek, and Lord of the Rings. Spam became a metaphor for getting a lot of something you don't want and never asked for.

[Tribune7]

The term got really popular in April of 1994, when two lawyers from Phoenix named Canter and Siegel posted a message advertising their fairly useless services in an upcoming U.S. "green card" lottery. They had posted their message a few times before, but on April 12, they hired an mercenary programmer to write a simple script to post their ad to every single newsgroup (message board) on USENET, the world's largest online conferencing system. There were several thousand such newsgroups, and each one got the ad.

Say what you want, it's a legacy.