I can't remember if it was Chesterton who said this, but it seems apropos:
"A pessimist is an unhappy idiot. An optimist is a happy one."
Catholics aren't called to embrace the idiocy of believing in some oracular maxim about everything being either wonderful or terrible. Things are what they are, and that's how we ought to treat a thing - as it is. That's the Catholic approach.
As for "negative attitudes" (another bit of insidiously popular New Age sloganeering) being prevalent among Traditional Catholics, well consider the condition of the world today: post-Christian, godless, perverse, Judaized, lustful, materialistic, cruel - in short, it's an evil age, the most evil age since the dawn of the Church, in fact - and it ought to be regarded as such.
The ѕуηαgσgυє of Satan has created more than enough diversions and distractions to turn our children into "optimists" - blind, acquiescent, capitulating "happy" (and therefore, useful) idiots. We will have truly handed our children serpents and stones in place of fish and bread if we're willing to do the enemy's work for him in this regard.