That is a goal of the OS project, not the browser project. There is nothing wrong about moving on.
> I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones.
Of course not. And if one set their goals ambitiously from the outset, they would be accused of being non-humble. There is no path one can follow which escapes baseless and inane criticisms.
> Of course it's ok to change, but you can also consider that as a precedent and take anything they say now with a grain of salt.
One can also criticize failure to change and adapt, and failure to seize and follow opportunities.