I don’t think anyone is telling On-One / Brant what they should or shouldn’t do. People are just expressing some sympathy or empathy with the OP and suggesting that if the same happened to them, they too wouldn’t be happy.
On the On One side – they can of course quite rightly stick to the absolute terms of the warranty. Or they can accept that doing so may not paint a particularly great product quality / customer service picture and see if they can find some way to keep that customer happy and to generate some good PR in the process.
None of us know all the factors that may or may not have contributed to the failure of the frame or whether those factors could be considered as reasonable or as unreasonable treatment.
There is no absolute right or wrong here but it would appear that there is an opportunity to come to some sort of arrangement that keeps all parties happy (or at least a happier than they currently are).
DB