True but it could be rightfully suggested that Takahashi was influenced by Tomino and his left wing views on the war; the Party was composed of people still mad at the Allies and Karma Houdini war veterans.
Technically, Layzner never got cancelled due to comparisons between the Gradosians ruling Earth and Japan ruling Korea in the early 1900s, what happened is that Sanyo, who were sponsoring the show, lost a lot of money due to a faulty heater that they sold killed its customer, and couldn't get any more money to keep Layzner going, as well as poor model kit sales. The only way Takahashi ended Layzner was with that Hallmark 2000 OVA as the ending.
Perhaps the Liberal Democratic Party was behind on the faulty heater deaths.
It wasn't just death by faulty heater, but also model kit sales not going so good, due to the fact Layzner came out months after Mobile Suit Zeta Gundam, and in regards to how Grados treats the Earthlings after conquering them, isn't that how aliens would treat the people they conquered?
Only because said aliens were informed that in a few years The Cold War would end with America and the Soviet Union fighting the aliens together; perhaps, they wanted to beat them while they're still at it.