The user is correct. I tried this on windows and the gamerules were also removed. I have checked the patch notes for the last couple of versions and can find no mention of Mojang removing this.
In Bedrock Edition you can turn patrol and wandering trader spawning on and off with the /mobevent command. This parity difference is older than the 1.14 update, so it is not a valid issue for the bug tracker.
The user is correct. I tried this on windows and the gamerules were also removed. I have checked the patch notes for the last couple of versions and can find no mention of Mojang removing this.