This is just wrong. Danish health authorities still offer and recommend COVID vaccines (two doses) for everybody, and an additional booster shot for everybody above 18. It is only the second booster shot which is only offered to people above 50.

See https://www.sst.dk/da/corona/Vaccination point 10

Quoting from the page that you have posted:

Why are people aged under 50 not to be re-vaccinated? The purpose of the vaccination programme is to prevent severe illness, hospitalisation and death. Therefore, people at the highest risk of becoming severely ill will be offered booster vaccination. The purpose of vaccination is not to prevent infection with covid-19, and people aged under 50 are therefore currently not being offered booster vaccination.