I haven't seen any compelling arguments as to this supposed conflict-of-interest with Blockstream, to be honest.
It's pretty simple. Blockstream is in the business of off-chain scaling. Probably both mainchain and offchain scaling is required for Bitcoin.
You can't expect those core devs to be objective. Because of their business interests, they are going to be slightly to strongly biased
against mainchain scaling, even if that is not in the best interests of the larger community.