Of course it is, and the naivety of webdevelopers that continue justifying a “chrome first” workflow is beyond irresponsible at this point.
Of course something can be irresponsible for many reasons but I think there is a solid argument that making a website that works better in Chrome than other browsers is morally irresponsible because you are encouraging more users away from more open browsers. (Which I guess is mostly Firefox at this point? :'( )