Open source has changed a lot recently. Most people/companies do open source to make money. The initial phase is just to make the software popular enough so that a money-making business can be built around it.
Frankly, I don't see anything bad with it. Those who don't want to spend money get it for free and those who can afford will pay for it.
Is it? I mean, how? The core Redis software is still open source as it's always been, with the same (well, improved over time) functionality, whereas the closed-source for-profit components are not even 'paywalled features' but clearly separate higher-layer products building on the core (visualisation, ML, time series, full-text search, graph structures, &c). To me this is a paradigmatic example of well-done open-core.
Frankly, I don't see anything bad with it. Those who don't want to spend money get it for free and those who can afford will pay for it.