Sure, of course, I would guess that basically everyone agrees with your entirely non-controversial opinion that you don't like seeing advertisements... but why can't they say "climate change"?
You note "Maybe it isn't even about the topics presented, but about the politicians and political campaigns in general.", which could hypothetically be true in another instance... but in this specific instance they approved the same ad by the same politician after the phrase "climate change" was replaced with "democracy".
They specifically, explicitly, wanted the phrase "climate change" removed. In this instance, it is clearly not about the politician or political campaigns in general - it is about the specific phrase.