Blacklist? I have never backlisted any altcoins, and this could be for the reason that I do not venture into coins' investments anyhow. I do my thorough research and even if they've not been performing yet, they would later, so I do not even go near the blacklisting, it's a huge word to say the list. However, there are many coins/tokens I will not go near, and I collectively call them shitcoins. This shitcoin of a thing is also subjective, which is why what many would call a shitcoin may not be shitcoin to me even as some people believe that all altcoins are shitcoins which I will never agree to.
Nevertheless, I don't think that I am ready to look at the coins below the market cap rating of #500 in ranking no matter what the coins pose to offer me.
I mean the ones you go "I would never invest into this" is the one you blacklisted yourself, which is probably enough. I have plenty of coins and tokens that I consider as things I would never put money into, don't you have any of your own that you would never put money into?
You say there are some you do not go near to, and that should be enough, think about those for a moment and that means you have a list that you are not going to invest into, and that is exactly what people are talking about when they say blacklisting something. Of course there is also an official blacklisting process, which you can do at places, but I do not think that you need to be doing that much to consider yourself having a blacklist project, just not investing is enough.