And I don't think you're correct. There are 5 menu items + log in + the API docs button on the main header. If you want all those to fit in a sub-standard width page, you're going to end up sacrificing readability in text. If you want to propose removing a menu item to make more space, that's an option, but just saying "I don't like the hamburger - they could fit the menu somehow" is not helpful.
What you do is fit the important stuff and hide the rest under a "more..." just because it ALL can't fit doesn't mean hiding everything is the only solution.
What is "important" in this context? Resources and About? Do you just hide stuff under "More" from right to left as you run out of space? How many people are actually going to click or hover on "More" to find out what's under there? There's a reason design trends have been shifting toward hamburger menus for smaller layouts - it's the best design choice for usability and lack of confusion once people get used to what the hamburger icon means.