Argument 1: Proof of stake concentrates wealth more than proof of work.
You can make that argument, but POS advocates have for a long time argued that proof of work mining has more economies of scale than proof of stake and therefore the opposite is actually true. Equating proof of work miners to the working class & stakers or developers as wealthy elites or rulers is so massively cringe it's tough to even read.
Argument 2: Ethereum is in active development, is planning to switch to proof of stake, has things like difficulty bombs, and therefore is somehow dishonest.
Decentralized blockchain communities come to consensus around different values and philosophies. Eth has for a long time been a community which values consistent iteration and improvement around fundamental aspects of the protocol. The transition to proof of stake has been known for years and years. There's nothing dishonest about any of this. If anything the community has been asking for faster iteration to solve high transaction fees and improve usability. Bitcoin's development stagnation works fine for bitcoin. Ethereum is clearly making the right move in continuing to improve the base protocol. Which as you mention is a huge, extremely complicated undertaking.
The article goes on to some cognitive dissonance about how Ethereum doesn't deliver on promises despite the fact that it just delivered a major protocol update last week... might as well throw in the dao hack and icos and whatever else in there and see if anything sticks. I guess with nothing to develop or build, bitcoin maxi's have a lot of time to ramble incoherently about Ethereum. And they probably always will.