True, sometimes taking the high ground is best but it comes with a cost if you are completely quiet and don't respond to the attacks.
I think it comes from Christian sensibilities.
Far from being aggressive like the Left likes to imply, Christians are commanded to turn the other cheek, give him your shirt as well as your cloak, and to be humble, meek and mild.
And we lose and things get worse. We just feed the enemy this way.
Time to sell your cloak and buy a sword, GOP!
That’s Scripture, too.
Until Trump, the Republicans more or less complied. They consistently took the high road and chose to lose with dignity (for example, Romney, McCain, Dole, etc.) rather than get down in the dirt with their scrappy opponents.
The very attributes that many Republicans criticize Trump over are reasons that Trump won the presidency - against an opponent that was all but crowned Queen.