Ahhhhh....you're trying to work out my my cunning plan......lol.

My theory is that there always more good people than bad.
Which would you prefer....
a) to be part of something that promotes freedom and free speech?
b) to be complicit in a user's nefarious ways?

Option 'a' gives you the same value added to your account as an up vote received from slime.

If you started flagging accounts he votes for, there is a big chance that it would backfire on you in a very bad way.

....not necessarily ( see no loss of vote value above)
People with sound ethics would not mind the disruption and messy comments section (for a short time), if it meant that this issue was brought to the attention of others (imo).
It would highlight malicious actors on the platform.
It would be of no loss , value wise, to the account being up voted for by wither.
(and the upvote value would be passed on by the account holder to me. i.e the malicious down voter would be adding to the pool of resources to combat him..)

There are a lot more good players than bad, to counter the abuse.
(this isn't about me, btw. I will continue to do it once he stops on my account and goes to another.)

It might lead to the option of declining rewards from an upvote from any specific account...imagine that..no curation rewards for malicious players.
That changes things...

I'm still ironing out wrinkles! lol.....