About five years ago, maybe more, Google started sending me captchas if I ran too many repetitive searches. I could be wrong, but it feel like most large platforms have fairly sophisticated anti-bot/scraping stuff in place.
Google does the same to me: Don't they know, I keep modifying my searches because their results sucked so bad I had to try 30 times to find the piece of information I needed?
Remember when github disabled searches for users who aren‘t logged in? Well, they just set the threshold for searches to 0 these days so they have de-facto disabled them again, this time avoiding the shitstorm.