Both sides had 1 year on TV debating this, a second referendum would be ignoring democracy, you would literally have riots on the streets especially with the yellow vest movement becoming very popular.
You act like the last referendum was the first for the UK to stay in the EU. You're wrong.
There is NO reason not to make a "second" referendum. Since then millions of young people became eligible to vote and millions of old people have died, which makes their vote worthless. If the result stays the same, so be it. But ignoring those millions of votes is definitely much more undemocratic.
The people that don't want another referendum know deep in their hearts that they will lose hard this time. Whatever brexit movement there is pales in comparison to remainers now. We have had many protests demonstrating this.