I haven't noticed this to be a problem. Can you go into more detail about it? Having multiple accounts has been an approved practice for a long time, so I think it would be helpful if you could point out the people that are giving negative trust to users simply because they have multiple accounts so that we can be more aware of their behavior.

FYI, I have given negative trust to many scammers on all of their multiple accounts because they are scammers and not because they have multiple accounts. I don't see anything wrong with that.

Also, I have heard that people try to cheat signature campaigns somehow by having multiple accounts, and they are given negative trust. TBH, I don't really know anything about that and I don't really care, unless the signature campaign people are the people you are talking about.