No one said it was illegal. But no one has admitted it.
You are wrong. Some countries, such as Switzerland and Singapore have legalized Bitcoin, and have even introduced laws aimed at its regulation. On the other hand, only a few countries (such as Vietnam and Iceland) have banned it explicitly.
Most of the governments have already come to terms that bitcoin is here to stay, so even if they wanted to ban it in some way they eventually though better of it. Yet there are governments that are either still getting the whole idea wrong or are just too stupid to accept the facts