That he had the cojones to call scripttardery for layout "performant" alone should set off your bullshit alarm.
Good rule of thumb? If you HAVE to use Javascript to control your layout, you probably don't know how to use CSS to build layouts, or are doing the type of garbage that shouldn't be on a website -- or web app -- in the first place!
But then that his "really basic HTML" has the X-UA set to edge bullshit, a lack of media targets on the stylesheet, and he put blocking script in the HEAD really should tell you all you need to know about this kid's qualifications to even flap his yap about it.
And yes, kid, as in "Old movie? Christ Tony how old is this kid?"