Your point would be?
Your point is the one which isn't clear. Here's what I assume you to be saying.
Major: Catholics don't negotiate with Rome.
Minor: The SSPX negotiates with "rome".
Conclusion: The SSPX is not Catholic (or behaves in a non-Catholic manner, or whatever).
As you can see, your point isn't clear. However, if it means what I assume it does, then it is flawed by using "rome" as equivalent to Rome in the two premises. It is also flawed in the Minor itself, which I deny. The SSPX does not negotiate with the Modernists.
Here's an alternative.
Major: Catholics must submit to Rome.
Minor: The SSPX thinks that "rome" is Rome.
Conclusion: The SSPX should submit to "rome."
I deny the Minor. The SSPX doesn't think that "rome" is Rome, or it would submit to it. It doesn't submit to "rome" precisely because it sees that "rome" is not Rome.