Answer:
Political events like a candidate rally are particularly tricky for companies, and sponsoring them could result in a lot of consumer backlash, specially from the people who are not affiliated to the sponsored politician or political party.
This is why many companies avoid political sponsorships or political statements, because politics is a very divisive issue, and while such an action could earn the company the loyal following of a few, it could also discourage a lot more people from ever buying their products.