Respect isn't given, it's earned.
And, the Cowboys haven't exactly been stalwart on offense of late, and let a group of second stringers on the Eagles run the ball very effectively. The 49ers have one of the best run designed schemes in the league, and will be a real test for this defense's resilience against the run.
Couple this with the overall lack of playoff success the last quarter of a century, and the skepticism is very understandable.
That being said, games are won on the field and not in the media. If the Cowboys want their respect, all they have to do is go on the field and get it.