I plan to do the same thing, I had this idea for quite some time, though not strictly just a LLM based bot.
The reason? Political topics are often dominated by those who have most resources, including more ideological zealots. I have no intention to explain things over and over again. Most people deserve to be handled by a bot if they want to to engage in political discussions, because they're just a biobot themselves (NPC meme).
Also, countries and corporation were able to hire PR agencies for quite some time. Then training activists and paying some people in India to post certain comments or vote in certain ways. A lot of politics was likely have been dominated by that.
Obviously it's better to make this so that it will be less obvious, but it also might not matter if certain people block such a bot, since the target are people which are not as convinced about certain issues. Just reading something with an argument they never heard before might change their mind. Some might be true for not being under the impression that everyone has the same mainstream opinion.
People will be more in bubbles with bots they agree with, and which they might often know to be bots, which are maybe framed as something likable like an anime girl.