Generally, yes. But if a large fraction of people are getting confused in a specific context, then you can say "don't word it that way", even if the wording is true when you consider it in a vacuum.
If putting the other brand name first causes consumer confusion in certain places, that's a problem, even if they're not lying or even doing it on purpose.
The ad can violate trademarks even if the site behind the ad is squeaky-clean.