While I support the ban on using Huawei's equipment in our communications infrastructure, I don't really see how it's justified to ban suppliers from working with them. In my opinion, that should only be reserved for extreme cases, like countries/companies violating nuclear non-proliferation agreements.
These sorts of export bans give the sense that Trump is either trying to use them as leverage in the trade negotiations, or maybe just trying to give a short-term boost to US-based competition. Either way, it doesn't smell right.
The downside of this sort of meddling is that other foreign companies will be less likely to source from US suppliers, in the future. That sort of trust in fair competition and open markets can never be fully regained, unless perhaps the US loses court cases brought against it for these actions.