By definition, tolerance (more specifically, political, religious, social and cultural tolerance) is the policy and practice of recognizing and respecting (accepting) the beliefs and/or practices (i.e. activities) of others.
Unfortunately, liberalism took tolerance to such extreme that it began to tolerate beliefs and practices that are literally driving the Western Civilization to a very real Hell. In other words, beliefs and practices that present a clear and present existential threat to the Western Civilization. Which makes liberal practices of tolerance genuinely suicidal.
More specifically, liberals tolerate so-called “gender equality” that leads to the suicide of the Western Civilization by “dying out”; “cultural equality” which inevitably leads to disintegration of Western countries into “mini-nations”; and, of course, Islam (the “Green Bolshevism”) which openly states its commitment to conquering and destroying all other civilizations and subsequently transforming our world into a global Islamic caliphate.
Which will in no time make it a very real Hell on Earth – just look at societies created by ISIS, Taliban or Iranian mullahs.
On a smaller scale, liberalism tolerates organized and street crime, human trafficking, prostitution, child pornography, pedophilia, drug and alcohol abuse, domestic violence and other ills of the Western society that can (and must!) be ruthlessly eradicated.