In terms of the current Right/Left dichotomy, there is little to practically separate an actual "Alt Right" White Supremacist from an actual violent Anarcho Communist. Both espouse violence in favor of debate, forgo personal responsibility in all areas of life except in the practice of extreme ideology, and squarely place the blame for perceived ills on others, not to mention both are fundamentally detached from reality.
Any addiction, including to ideology is unhealthy. It substitutes fantasy for truth, and destroys the agency of its victim. In the case of ideology, it is the beam in the eye of one trying to remove a speck from the opposition, or in this case the black hood on the one trying to remove the white bed sheet from the other. Fortunately, vocal minorities in both directions do not generally speak for the majority of people simply more concerned with their day to day lives than media sophistry and rhetorical noise. The ratings though do seem to benefit.
On the other hand, the hidden deception, far more banal because it passes as virtuous, possesses those claiming a position of faith in opposition to one of the two extremes. In the West, this often means Christians who may perceive themselves as boldly opposing injustice when they decry the rise of Fascism, Communism, Islamism, whatever happens to be readily and obviously worth opposing. Evil must indeed be opposed by the person of faith. It must be named, defined, its victims protected, if need by at the greatest risk to the person of faith. We rightly remember those from the past who have done this as heroes. However, just as ideological extremes mirror each other the farther apart they become, so too does moral outrage become moral panic the more fashionable the object of that initial outrage.
Both extremism, and moral panic are fundamentally disconnected from the complexity of the world. Both grossly oversimplify day to day existence. Both are evil manipulations of the human tendency for availability bias, and both are far more in keeping with mob behavior than heroic courage. Furthermore, both are fundamentally lacking in introspection.
For the person of faith, the beam to be removed is the deception that the methods of the City of Man can bring the outcomes of the City of God. It is possible to work to good effect in the City of Man, but using its methods to further the latter will turn in into the former far more surely than the alternative. Evil must be opposed, and preferably by rules it does not play and cannot beat. Leftist and Rightist extremism are both ridiculous at best and abhorrently sinister at worst. However, using one to combat the other, focusing on one while ignoring the other, or allying with the methods of one to confront the other, no matter how noble on the surface, is nothing short of moral prostitution, and idolatry. We do not look to win the game, but to destroy it. It is not that such idealism seeks too much, but rather too little.
The methods of the City of God are faith, hope, and love. Forgiveness, reconciliation, compassion, mercy. It is ridiculous to expect these virtues from the City of Man, neither is it its place to exhibit them. The best it can do is equality before its laws. To think otherwise ignores history. The methods of the City of God though are firmly the responsibility, and unique capability of the individual and community of faith. Even in a totalitarian regime, the most important problems to fix are often right next door in the form of those needing shelter.
In general, if it's easy to condemn, it isn't the deeper problem. Moral courage generally means taking a stand that actually assumes risk. Both ideological extremism and moral panic are hubris fueled mass self deceptions. The real extremism is to put childish utopianism behind us, and seek to change what we have the opportunity to. Perhaps with faith in these smaller works, greater ones will be opened. The homeless alcoholic, teen mother, depressed family member, etc need your help as much as the nebulous masses. You will sooner see results with such skin in the game.