That's because the PM's party brokered that half-way deal with EU against the will of the people, after they had voted no to EU for the second time[1].
Not saying some of our export companies aren't enjoying the access to EU, but the people was against it.
[1]: https://en.wikipedia.org/wiki/1994_Norwegian_European_Union_...
Since 1994 the will of the people had a lot of time to express itself...