If you want to know why people in the mainstream are beginning to dislike leftists with more passion than normal, the reason is looking you in the mirror. It's about the survival of a civilisation. Leftists tend to hate anything they don't control, so if a nation or an entire civilisation is not being steered the way they like, they will not hesitate to spike the guns, blow the barricades, and stab the civilisation's defenders in the back.
If western civilisation goes down, only authoritarian principles will survive as the nucleus of replacement civilisations. Fundamentalist Islam, leftist hellholes like North Korea or the coming Venezuela, and warlord-ruled states such as Zimbabwe, Cuba, Myanmar, Bolivia, and so on. Japan might survive as a quasi-western state, if it learns to develop effective robo-weapons, nano-weapons, and space-based weapons very quickly. Otherwise, Japan will go down, like the intentionally sunk (by leftist factions) states of the west.
Prime power centers for the left in the west are: the universities and education unions, the media centers (news, publishing, and entertainment), the arts, labour unions, and most civil service departments of governments other than practical, performance-based departments such as fire, law enforcement, and EMS.
Leftists "spike the guns" by subverting actions of the military and intelligence communities that are aimed at enemies of western civilisation. The New York Times is quite active in that area. Leftists blow the barricades by preventing the enforcement of immigration laws and border enforcement. Leftist stab the defenders of the west in the back in too many ways to mention. Only someone indoctrinated in a leftist university department would fail to list several examples.
There are no perfect nations or civilisations. The civilisation of the west is the freest for the greatest number of its citizens.
The bloodbath suffered by Cambodia after the Khmer Rouge seized power will be nothing next to the deluge of blood should the west fall.
Leftists will get us all killed--even themselves. Leftism is a quasi-religion, an indoctrination-dependent ideology. Leftists immediately try to purge their immediate environment of non-leftist elements--because they can't take the implied threat to their own beliefs. The beliefs are not supported well enough for the most part, to sustain doubt. All doubt must be swept away.
When only leftists are left--the incompetent society in spades--things will quickly collapse, and the authoritarians will make blood flow in the streets. That's why I don't like you. Because you're going to get me killed.