There are many users operating other browsers beyond those giants that desire to be Chrome in look, feel and technical underpinnings.
There is also Palemoon- I use Palemoon 32bit all the time - there is waterfox, there was cyberfox, there are other browsers for Windows. Basically, what is provided by the internet for the internet needs to be browser agnostic, ie. it needs to work on all browsers and not just on Windows but on all o/s including ReactOS!
If we accept that internet provided tools are to be browser-specific and not work in others then we might as well accept that applications can be just as o/s specific and all resign ourselves to abandon the pointless task that is ReactOS and adopt the two-headed behemoth that is Windows running Chrome for ever and ever.
PS. Palemoon runs Mattermost perfectly.