Depends, are they making front-ends for websites and actually care about accessibility, or are they sleazing out web crapplets that give a giant middle finger to users with accessibility needs.
Generally speaking (and this is a gross over-use of the wide paintbrush) off the shelf scripttardery is by it's very nature -- and this is more so for using off the shelf libraries -- telling users with accessibility needs to go plow themselves. It rarely has any business being used for websites thanks to the gross inefficiencies, massive overhead, and general ineptitude of development associated with it. Hence the "unwritten rule of JavaScript" where "If you can't make a fully working page without JavaScript first, you likely have zero damned business adding scripting to it!"
Basically if on the front end the page "needs" JavaScript to deliver content, you've probably screwed up and utterly ignorant of things like the WCAG, accessibility norms, semantics, separation of presentation from content, etc, etc... Good client side scripting should enhance functionality provided by the markup, and NOT be the only means of providing it. This is where idiocy like angular.js, backbone, or ember falls flat on their faces.
Now, that said -- that applies to CLIENT SIDE. node.js (which is what I assume you mean, not seen people omit the .js part before) is (usually) a server-side technology. Front end developers should have a general idea how the back-end they are coding for works, so they have some idea what to provide the poor sods working on the back-end to integrate into the codebase. Sadly regardless of what's being used on the back-end be it node.js, PHP, Java, .NET, Ruby, whatever, the people working on the back end -- and indeed a lot of people working on the front end -- do not know enough about HTML, CSS, or accessibility to even be touching front-end code. They are utterly and completely unqualified to even be doing any aspect of the work -- just "view source" the default code vomited up by turdpress or 99.99% of the nube predating scam artist BS at the various template whorehouses like ThemeForest or TemplateMonster for proof of that.
It's truly disturbing how often you'll come across back-end developers working in things like .NET or PHP who will actually say "I know PHP but I don't really know HTML and CSS"... and all I can think is "Then how the string of expletives omitted are you even qualified to be writing a single line of code when the entire POINT is to output HTML?!?"
To that end, I wonder how in blazes people can even put up with using node.js to output a front-end. You're stuck either building a DOM and wasting time parsing it back down to markup, or dicking around with garbage like innerHTML which we just spent a decade and a half being told to stop using. Generally speaking creating markup -- aka a frontend -- from JavaScript inhales upon the proverbial equine of short stature, and is why as someone who actually understands HTML, CSS, separation of presentation from content, bandwidth limitations, limitations of the medium, content first development, and accessibility norms, I cannot fathom why anyone would use node.js to output their front-end by choice over something designed to work with HTML like PHP.
Though I can see how it's useful to output data to be handled by client-side scripting, you have to remember that only really serves a purpose if you are going to again tell certain groups of potential users where to stick it... Like those who block JS from lack of trust or facing bandwidth caps, or those don't have access to JS thanks to their workplace locking it out, or users for whom what JS does flat out isn't accessible.
Really though like anything else, it has to be treated as a right tool for the right job scenario. Far too many people using certain languages -- and JavaScript/ECMAScript is the poster child for this right now -- have the "hammer is my only tool" mentality; suddenly every problem looks like a nail... and whilst Uncle Red may refer to his hammer as a flathead screwdriver, you pull that stunt no amount of duct-tape is going to fix said misuse.
More than anything, that's the real problem; people learning just one thing, then assuming it's the answer to every problem...
Bottom line, IF the front end you are developing is going to be tied into a back-end language -- be it Java, JavaScript (via node.js), PHP, .NET, whatever -- you SHOULD have a command of that language so you have some idea what to hand to the people working on the back end and/or how to explain it! Does that mean ALL developers should learn it? No... but if you're creating a front end for it, you damned well better know it!