Technology are always developed this way: learn (sometimes not so nicely), catch up, and then innovate. An random country can't innovate itself to a 5G/technology super power immediately.
What I never get from this accusations is, why aren't these company suing to ban Huawei sales if the copying is so blatant. Have they not heard of the patent system? Is Cisco/Nortel suddenly a small company that cannot afford to sue and/or have a vast arsenel of patents?
First, Huawei's sales in the US already is quite limited to have any impact. Second, you can't win any sales or import injunction on 5G SEP violation.