When Government clearly states something isn't legal people automatically assume that means it's illegal.
They didn't say it isn't legal.
"legal" and "legal tender" are totally different things
If something is not legal, then it's illegal. If someone tried to pass off bitcoins to you as legal tender they could be charged as the tender isn't legal (aka is illegal).

Comparing apple and oranges, here there is a prime example. Saying that bitcoin is not "legal tender" does not mean it is "illegal tender", nor does it means it is "illegal".