Those other products are either unlicensed or have different licenses than allowed for Blu-ray players. When Sony, Samsung, Panasonic etc start offering BR players with ISO support then you can complain to OPPO for not keeping up.
We went over and over this earlier in the year with the ISO on the -93 fiasco.
I am not complaining, but just hoping for future support and change in the way physical music and movie discs are sold. I am hoping for the ability to play lossless media that I paid for without having to put in a spinning disc. But because we all know that HDD fail, I would still like having the physical media in storage.