No it isn't. Unless the person shutting you down is a police officer or a government official, or anyone with power who has the ability to arrest you, your rights aren't being violated. Under law you can say whatever you want so long as you're not inciting violence or yelling fire in a crowded theater, but that doesn't mean other people can't use their own free will to call you out if what you have to say is in any way offensive. You want to know what real censorship looks like? Go to Russia and say anything remotely critical of Vladimir Putin and then tell me how bad you have it here.