I don't care what the attack is responding to, nor do I care what services are being provided.
If, when I visit your site, your site causes my browser to participate in a DDoS attack without my knowledge, your site is malicious.
If you didn't care about the service you wouldn't visit their website in the first place, in which case there is no problem.
If you didn't care about the service you wouldn't visit their website in the first place, in which case there is no problem.