I dont want to make your choice for you, but I still remember displayninja's review, and I feel it is a reasonable quote.
They suggest if your primary use is the PC and you want previous levels of colour saturation then the LG850 is the better choice. The sRGB was a big factor in my decision.
As to why so many manufacturers are skipping over it, who knows, likely they dont want to make a perfect monitor (as previously stated, they perhaps want people to buy multiple screens for multiple purposes), or they just cutting too many corners for cost control.
I agree the reason given to you is BS, on the LG, when HDR is activated it forces the vivid profile to be used, the sRGB profile has no affect at all on that.
Also be aware of some new screens that have sRGB but do not allow brightness to be adjusted, luckily hardware unboxed has been calling them out, as that is utterly ridicolous.
Also there is the LG 27GL83A, same as the LG850 (nano ips), but its an sRGB monitor, so not even a need for an sRGB mode as its natively sRGB.