What issues people feel they need an excuse for, instead of just openly taking a position, is important. It says a lot about what they consider fully legitimate and what they consider more questionable.
For example, no one needs any kind of excuse to be pro-freedom, pro-science, or pro-education. People take those positions proudly.
But people do need excuses to mistreat people they label "mentally ill". They don't just say, "I don't like him, so let's use force against him!" Psychiatry makes up a bunch of excuses about medical science to help legitimize their otherwise-illegitimate actions.
Global warming is also an excuse. The greens don't just proudly say that factories and electricity are bad. They say we're forced to cut back on industrial civilization or else the world will be destroyed. They feel they need a really strong, compelling excuse for opposing material wealth and technology.
The political left doesn't want to admit they are anti-liberal. They feel they need excuses for being anti-liberal. Their favorite excuse is to lie and say they are "liberal" and "progressive". And many people claim capitalism is pretty good (they find it hard to proudly and fully oppose capitalism), but they use excuses about "excesses" and "public goods" to legitimize a mixed economy.
People often feel the need to have an excuse for shutting down discussion and being closed-minded. They don't just say, "I am opposed to critical discussion with people who have different views than I do." Instead they make excuses about how they'd love to discuss but they're too busy, or the other person is ruining the discussion by being too unreasonable.