That’s because the policy isn’t derived from first principles, it’s a flexing of relative muscles. Google knows that small sites don’t have any choice but to comply with their guidelines. They also know that if they start filtering out LinkedIn results, if people are looking for something they expect to find on LinkedIn, they’ll go and search LinkedIn, possibly even before they search Google. Google will not allow that to happen.
Also, Google doesn’t also compete with those companies. I would bet if it were someone who they were competing with on another vertical , they’d be enforcing this policy.
