It’s within anyone’s rights as website maintainers to block malicious IP addresses that scrape or otherwise within their discretion.

Nobody is legally forcing websites to allow access to everyone, and accordingly, nobody is altering the law by blocking access to people (crawlers, hackers, spammers, malcontents, or anybody really) that they feel are not welcome. So exercising one’s existing rights isn’t an act of making or altering laws.

I suggest reading up on what robots.txt is to further understand this.