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.
I'm sure they have reasons that can be speculated about (probably money), including that they don't want to run controversial ads though I don't know if they have imposed the same criteria to different takes on the same subjects.
I think it's regrettable and irresponsible that climate change has been allowed to become such a controversial topic, although this has been a decades long effort. It might be they don't want to lose viewership by broadcasting certain topics. But also,
Very possible they get $ from advertisers who pressure them to avoid the topic
Seems to me most likely their decisions are financially motivated, but this is just a guess.
I admittedly don't know all that much about Hulu's policies or history in regards to the advertising they choose to accept. It may very well be they have other motives, are trying to appear nonpartisan by allowing Ds to advertise but giving them criteria about what they can say, how they say it.
Hah! Good point. The reason they don't want to hear the word "climate change" probably has a lot more to do with money than politics, they may just be slipping it in under the cover of other political advertising restrictions.
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.
https://archive.ph/VNGYQ