Why not? Because it is a fact you don't want to hear? I do not hate either Dak or Romo. Both have their strengths and weaknesses. Both (to date) have had to deal with Garrett and his deficiencies. I am happy as a Cowboy fan to have both of them play for this team.
That said, it is a fact that in Romo's 9 years as a starter he only twice had a defense that finished better than 15th in points allowed, and in yards allowed they only finished in the top 10 three times (his first three years). These are facts. The years we struggled at 8-8 our defense was ranked 16th, 24th, and 26th. We complain about last year's defense yet they gave up less points than any year Romo was a starter.
https://www.pro-football-reference.com/teams/dal/index.htm
I did not bring that up to bash Dak, or "hate" on Dak. The issues with this team last year were not him (though I believe he is not without some blame). I bring them up because it happened, nothing more. Not wanting to hear about it doesn't change it.
While we are on the topic. You mention hating Romo because of all the years he lost to Philly in the last game (it was only once by the way), so how do you feel about Dak's last performance against Philly with the playoffs on the line? 25-44 for 265 yards and a 74.5 rate? Or how about his 21-34 for 181 yards two interceptions (51.2 rate) in a must win game against Seattle to make the playoff's two years earlier? If you hate Romo for his bad games why does Dak get a pass? Both of them had bad games, should we not hold both to the same standard?
Both QB's basically have identical numbers through their first 4 seasons as a starter. Romo made the playoffs 3 times (1-3) , Dak twice (1-2). Regular season (first 64 games): Dak 40-24, Romo 41-23. Both made the pro-bowl twice. Right now there really isn't much to "hate" one over the other if you look at it from the same point in both their careers. Romo improved, (sure he couldn't get to the Superbowl - which to me has more to do with things other than Romo) and, I believe, Dak will too.
Hopefully replacing Garrett (6 years too late) will finally allow this team (and QB) to get somewhere we haven't seen in a long, long time.