Disagree in this specific situation (generally yes) - "XYZ alternative" is about as clear language as you can get. Nothing sneaky about it.
Hopefully the metrics show that the latter is mostly happening.
It's only fraud if the advertiser counterfeits XYZ's brand on their website.
The ad can violate trademarks even if the site behind the ad is squeaky-clean.
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.