Hi,
I got the same problem at my site with Sparkling Theme.
I created the topic before I saw this one: https://colorlibsupport.com/t/menu-dont-work-for-mobiles/
MY website: http://www.autocadblog.cz
The problem is with menu items that have any sub-items:
– You can’t unroll them in mobile
– The link of main item is only “#” so the link dont go anywhere…
BUT If I go for the GetBootstrap.com demo that you posted then it works fine… without any problems. So its not only bootstrap, but there is something wrong with this theme and mobile users 
If we dont solve this, then I will have to implement some mobile plugin and I would rather not
Screenshot of the problem:
Screeshot of my getbootstrap.com DEMO: