Of course yes, why the hell go throw the worries of having a legal system and legal forces to enact it when we can have some random vigilante telling apart what can and cannot be done.
This phenomenon is called "free speech", perhaps you've heard of it. Anyone is free to say, on their web site, whether a particular sender's email should be accepted or rejected, and why. And it goes without saying that everyone else is free to either agree, or disagree and continue to use their own internal policy for email acceptance or rejectance.
I have found that these cries of vigilantism tend to come from those who have a peculiar belief that these so-called vigilantes have somehow hacked into million of email servers worldwide, hijacked them, and reconfigured them to reject email from the targets of those vigilantes' wrath. This is, of course, utter horseshit. The individual owners and operators of all those millions of email servers have specifically and intentionally configured their mail servers to follow the recommended mail acceptance policy of their chosen third-party blacklist. Nobody held a gun to their head, and forced them to do so. They own their email servers. They pay their electricity and bandwidth bills, and they have every right to configure them in whatever way makes them happy.
And the so-called "legal system" is 100% behind them. Fortunately, at least in the Western world, private property rights still enjoy 100% backing of the legal system. I have never read of any legal decision, that survived an appeal, which forced the owner of the email server to accept or reject email from anyone they wish, for whatever reason pleases them, and on whatever it was based on. Quite the opposite -- there's actually established case law that determined that privately-owned Internet providers are free to blacklist anyone, and for any reason, which includes third-party blacklists, which I'll be happy to cite.
That is the cold, hard truth: nobody has a civil right to email anyone, and every other privately-owned email server operator is free to refuse to accept email from anyone, for any reason. Whether it was due to their own decision, or by delegating this decision to a third-party blacklist. That delegation, after all, is still their own decision to make. Like I said, it is their email server, and they have full control of it. And it they decide to delegate some control over their email server to a third party, they are 100% within their rights to do so. And neither you, nor any other spamming parasite, can do anything about it.