Like I understand and respect why one might attend an independent, SSPV, (etc.) chapel for all sorts of reasons. But Rome has *specifically* said that people are allowed to attend the SSPX. like they were asked about it in the 1990s, and they said in the strict sense you could go, and that it would fulfill your sunday obligation. So its easy to imagine why someone could see that situation as canonically preferable, agree or not.