That's quite the condescending comment. The 'ethical' part is likely referring to using visitors' browsers/CPUs to do your compute work without getting consent

That's quite the condescending comment. The 'ethical' part is likely referring to using visitors' browsers/CPUs to do your compute work without getting consent. Parent post also mentioned the bandwidth usage is high so you're not only using the CPU but using up a visitor's bandwidth (many of whom have low monthly limits).