My advice is to take a page out of WikiTree's help page on being courteous:
When someone sounds rude, assume that they don't intend to be.
Be the bigger person. Treat them as you would like to be treated, not as they are treating you. Even if a person is rude to you, don’t be rude back.
I will note that the message posted by the other user does not appear to be directed at you specifically, as it was posted to the profile and not directly in reply to you. From the shape of it, I'm guessing similar merge attempts have been made in the past and this other member is perhaps venting about being repeatedly pestered. (Plus thrown on top of it, how we're all under a bit of extra stress these days!)
Having other folks edit profiles without having read the full profile is inherently frustrating. That happens to all of us who manage profiles. I know that I've complained about the Fact-Fixers "correcting" algorithmically identified "errors" and it makes me bristle a bit.
Identify a way to help. My own approach would probably be to add a "disambiguation" header and details on each profile. e.g. Eilbeck-9
Still, even if this other user did so, there's no guarantee that others will read it, is there? Given what you've already said, it seems that you would have likely missed it. But honestly it's our responsibility to be conscientious and to read both profiles before merging. (It's a part of basic courtesy in my view!) Failing to do that begets sloppy genealogy... and frustrated comrades.
I would advise against seeking an MIR as there's a risk that by immediately escalating a situation that you could cause someone to walk away. Unless that person is a complete jerk, it probably isn't in the community interest. You can be the bigger person here.
Additionally, I will also note that it is not good practice to air dirty laundry in G2G because every edit and merge proposal that you've made is public: You may as well have just linked this question to the other user's profile. Because we can all follow the links, and I think you know that. Hence your posting this becomes an act of online shaming of the other member. That's not helpful, nor good for the community either.