Because not blocking these tools causes additional operational costs.

For example, higher return rate for online shopping (because the tools didn't buy the correct thing, or maybe they bought something that they shouldn't have).

Or, the tool ignores the adverts on an ad-supported website, intended for humans, basically just adding costs for no benefit to the site.

Or, the tool wastes customer services' time on something that ultimately the agent's operator didn't even want in the first place.

They're just off the top of my head.