It's a silly product, but as far as being over engineered, it looks like it's about what I'd expect for those requirements.
If so, you may have noticed the jack you used didn't have several huge CNC machined aluminium parts, a seven-stage all-metal geartrain, or a 330v power supply and it probably didn't cost you $700. Probably it cost more like $40.
And sure, a consumer kitchen product needs to look presentable and you don't want trapping points for curious little fingers. But even given that, you could deliver a product that worked just as well for just as long at a far lower BOM cost.
You can achieve the same goal (getting juice from diced fruit without cleanup) much easier with different requirements. The post mentions that.