The evidence for this is so ironclad, I’m not going to bother addressing the very thin arguments against it. How could you argue against a consensus of professional security analysts?
There is no evidence, so whatever 0 evidence you have might be ironclad or anything. There is no consensus either. Unless few people “believe” is a consensus in a community. The link you provided clearly states that some sources inside believe, which means no evidence what so ever.
Get tinfoil hat off please.