I don’t think there is any need for a definition of liberalism other than “minimal government intervention in individuals private affairs and in society mutual respect and tolerance.”
The people who call themselves liberal these days are anything but, they are intolerant, authoritarian and obsessed with regulating all manner of things in which we should have freedom of choice. They are particularly hostile to free speech to the extent that news crimes have been coined, e.g. hate speech, and in other areas of life they are leading us back to medievalism by reintoducing offences such as blasphemy for those who make valid criticisms of the Koran, though you can say what you like about The Bible, The Talmud. the Baghavad Gita or the holy books of faiths other than Islam.
A liberal is tolerant but understands that we can tolerate without celebrating, I have detailed my equivocal attitude to same sex marriage here before. When that controversy was at its height however, I attracted some hate attacks for my indifference. I was called a fascist and worse for saying, “we’ve had same sex civil weddings for years and most people are happy with that, as for the religious part, leave it to the churches, synagogues, temples etc.
Equality has always been a major plank in the liberal platform, but what equality. We were supposedly all equal in the eyes of the law, though that principle made exceptions for the rich and powerful, and liberal governments in the 19th and 20th centuries promised, and tried to deliver equal opportunity. Equality of outcome is impossible and the kind of equality that comes from massive social engineering projects as in Soviet Russia and Communist China has always wrought disaster for those it was intended to help.
We have always had laws putting limits on free speech but thanks to liberal and politically correct politics they are not enforced equally, fifty years ago if sombody had said in public, “all who worship Offler the crocodile god* must be killed, their faith is evil,” would have been in trouble.
Yet now, although Humanists, atheists, Christians, Jews, Hindus, Buddhists and Shamanistic Animists can get in trouble for pointing out that Islam does not respect human rights and condones abominable treatment of women, but Islamic fundamentalists can publicly call on their followers to “kill the infidel” or lobby governments for “the destruction of Israel and the purging of Zionists” (as one actually did at the Al Quds day rally in London this month) with immunity.
This is nothing to do with liberalism, it is virtue signalling hypocrisy.
We would do far better to recognise what is not liberal that wasting time arguing over what something as nebulous as liberalism is.