Not at all.
Views about the company you work can be freely expressed within the company’s platform and even outside publicly.
In fact, good companies promote employees to speak out and express their views regarding the working environment, policies, etc.
Employees voices are a good way for organizations to mend the issues internally rather than letting it brew and affect their business or an outsider pointing it out.
The only thing to keep in mind while expressing your views publicly about your company is that you don’t disclose any business or work details that is prohibited by your contract and also to maintain decorum.
I would also add that its important that employees speak out so that issues get addressed by organizations and it would be in mutual interest and also the software professionals community in general.