Mainline pilots gave up scope and allowed regional jets on their turf because management enticed them with increased pay/benefits as a reward OR because bankruptcy courts forced them to.
For those that took an increase in pay as a reward for loosening scope, and for those that felt they were above flying turboprops or regional jets.. YOU created this mess. YOU were the real tools managements utilized to create a new era of whipsawing aviation labor. Your self-centeredness and lack of foresight was the beginning of the end of our industry.
As far as the RJ goes.. it started in the 1990s as Delta allowed Comair to explode on the scene with their new CRJ100s. Maybe they didn't know any better and couldn't foresee the jets taking over long non-regional routes and becoming the new hub poachers but they should have.
For those who had bankruptcy rulings force violations of their scope and allow 70-90 seat RJs on their turf, you were screwed by bankruptcy laws that need to change. There is a large movement industry wide to change bankruptcy law to favor airline labor. I suggest donating to your union's political action committee or something.
Changing the name of the Regional category as a political statement is one of the dumbest and most fruitless ideas I've come across on this site. What's next.. should Bombardier and Embraer be lobbied to call their machines Contract Jets or maybe Fee For Departure Jets?! Don't forget, plenty of wholly owned subsidiaries fly them too and are not contract carriers.