My bad, I didn't know this. I'd assumed that the Dutch had always been more liberal than other European countries, considering that they had significant religious freedom as the rest of Europe fought religious wars. I think the Netherlands were the first country to legalize same-sex marriage as well, and Amsterdam is well known for it's drug culture.
The Dutch fought a religious war for 80 years: The Eighty year war. The Dutch republic was in some ways more liberal than other countries. There was more religious freedom, more personal freedom, more political freedom and more economic freedom. But the Netherlands in the 19th and early 20th century certainly was not as liberal as France or Britain or even Germany in some ways. The thing is, countries change over the centuries. Sometimes The Netherlands was more liberal, sometimes it was more conservative. This is true for all countries. You can see the same thing for the USA.
When we are talking about Alternate History, everything is possible. The Netherlands could end up as a very liberal country, or as a very conservative country. It depends on what happens to it. And to the rest of the world.
In short, you can decide.