Confusing JSHint errors and pop-ups

I'm a little confused at these new (?) JSHint "errors" I'm seeing scattered all over our .js files now:

I already know 'let' is available in ES6... why is this a red squiggly underline error?! What am I supposed to do here?

What? When did this become a rule? Double-quotes and single-quotes work the same way in JavaScript. Why must I always use the Shift button with my quote button in strings? That's only nice when you need a word contraction or I want to use single-quoted text inside of a double-quoted string.

I'm confused by this... I don't even know where to start. It's a typical check for 'if this thing is not truthy'. What's confusing about it?

The full line is like this:

`if (!$('input[name^="some_thing[here_yay]"]').length > 0) {`

OK maybe it could be written better (maybe wrapping the `left > 0` in their own parentheses), but otherwise I don't know what's confusing about it. Since when do computers get confused? That seems a bit overly-anthropomorphic.

Unlike normal "errors" I see in PHPStorm in .js files, where hovering over their squiggly underlined text would pop up a nice explanation then a suggestion to select to "fix" it, there's no explanation, strange/cryptic errors, and no clickable suggestion (like with `var`).

I mean, if JSHint is just like "It may be a little more readable if you kinda did it this other way, that'd be grrreat", then why use red squigglies as the default?! I always see red errors as "REALLY BAD!", not a stylistic or subjectively-readable thing. Now I need to go through each one and lighten the color so I'm not distracted? Maybe this thing is just better disabled somewhere...