No, we should not positively discriminate in favour of all non-Protestant perspectives
Our site aim to welcome Jewish, Christian, Atheist and other viewpoints as long as they take seriously the process of understanding the Biblical texts should not be understood as an aim that we end up with an equal mix of participants of each group1. Rather it should be understood that as a site, we are about the 'Biblical texts' and not concerned with religious beliefs2 and traditions per se, but only insofar as they intersect with the Biblical texts and their interpretation
Protestants are probably highly represented here because of the doctrine that the Bible contains all knowledge necessary for salvation and holiness. This does not mean that other traditions do not care deeply about the texts and their interpretation, however there is a strand of Protestantism that elevates the texts above everything else, and a site that is explicitly about the texts and nothing else is likely to be especially attractive to those folk. In other words, Protestants are by and large going to be attracted here for the right reasons: ie that "they take seriously the process of understanding the Biblical texts". Therefore to embark on a policy of discriminating against them just for being Protestant would undermine the foundation of the site.
I'm not at all arguing against promoting the site to particular individuals or groups. I am personally very excited when someone from an unfamiliar perspective starts contributing and saddened if they leave. However positive discrimination should not be site policy. The correct and well established approach is to continue to affirm that contributions should show enough of their working to make them useful to folk who don't necessarily agree with their conclusions.
1 however you choose to delineate groups!
2 or religiously loaded words