Because we live in the most politicized time in history, enabled by social media. We also have the largest proportion ever of mentally ill and under/unemployed people in America with nothing better to do, no real career and/or family prospects, so they must latch onto trying to further their feel-good ideologies to give their lives meaning.
It's incredibly ironic that the left, originally the party of labor, is so strongly protecting illegal immigration. When you let in 20 million low skilled workers from different cultures into your country, who do you think suffers: capital or labor? Who feels the pressure in rising housing prices, job prospects, rising crime in cities, etc?
The other ironic part to this whole situation is that the current administration goes so hard on their rhetoric and marketing but ultimately are deporting less people than ever before. Everyone is losing here, and the American Empire is fading away, eroding from the inside out.
> Beware of falling victim to the easy dismissal of 'more people are less rational and/or less informed than before', a variant of 'this person who doesn't agree with me must be less rational and/or less informed than me'.
Your explanation doesn't actually explain any difference in root cause between now and a mere 5 years ago, so it doesn't explain the difference in behavior.
Something else must be different. Try asking some of the folks you "oppose" what it might be.
