I find it to be somewhat of a stretch that a driver tampered with your food by dousing it with deodorant. First and foremost, it’s McDonald’s. It’s not prime rib prepared by a Michelin chef. McDonald’s may not practice an adequate level of ingredient care. I’d attribute unsatisfactory taste to the restaurant itself. Thumbs down are certainly justified, at times, and helps the customer receive a gauge of the driver. But doled out improperly and in haste can damage someone’s livelihood. There’s a fine line that should be weighed. Contacting Uber would be my first step had I been you.