I don't work in marketing or for amazon so this is a complete guess, but those ads may just come up when someone searches for "yard sign" or similar prompts. Obviously you have Trump in your search as well, but you also have "yard sign." Or maybe the algorithm detects you searched for political yard signs and that's why those are the ads. Again, disclaimer, I don't work in marketing, but someone does and for some reason your search fit the bill for those ads.