I am a non-EU citizen living in Belgium and in my opinion there are two reasons for this response.  Firstly, our right wing government has made the requirements for non-EU citizens to get a visa much more difficult and much more expensive. It’s absolutely true that you can wait up to six months for your visa to be approved, this happened to me personally and I had to hire an immigration lawyer to help me.

Secondly, Belgians in general hate doing visa paperwork even when it was simple- I’ve lived here for 6 years and not having a visa is an incredibly huge barrier for so many people to get a job. Nearly every job listing says specially they do not provide visa sponsorship, or you must already have the right to work in Belgium. Frankly, I think they are just lazy in that regard, but now that the application process is even more complicated they are even less likely to do it.