Right here, right now, they can be compared to guns assuming this was an attack. Were it not for car-centric infrastructure, a car couldn't even have reached this crowded festival. There would've been trivial safety measures like bollards in place, but because we as a society collectively value vroom vroom over human lives, they weren't in place. With nine eleven killed and twenty injured, it was comparable in devastation to a mass-shooting. Just like when the US values pew pew over human lives, there are mass-shootings.

But you're right: they aren't the same.

• Cars kill over one million people per year, and they injure and maim many, many more than guns do.
• Cars are unnecessary in the vast majority of cases, but they're shoehorned into cities thanks to the enormous lobbying power of the auto industry combined with the widespread, entrenched propaganda that said lobbying has spent the last century producing. We'll rip out safe and affordable transit to make room for these financial black holes, but even the most tepid attempt to push back on this takes decades of activism only to be met with a ridiculous half-measure in favor of cars or nothing at all. (Actually, this last bit does kind of sound like guns in the US.)
• We willingly subsidize cars (tax credits on EVs, free parking, parking mandates, vast road networks, etc.) instead of building the kinds of infrastructure that largely obsolete cars to begin with.
• Cars are absolutely destroying our planet. They're one of the main sources of greenhouse gases, and car-centric infrastructure even exacerbates a major effect of climate change by destroying greenery that absorbs some of the heat (which consequently makes people more likely to drive in air-conditioned cars; rinse and repeat). They additionally spread particulate matter into the air that puts (especially poorer) people who live near major roadways at substantially increased risk of health issues. They divide populations of wildlife, and I could just go on forever.
• Cars are heavily indoctrinated into children as a rite of passage into adulthood that everybody should own. Almost no consideration is given for those who don't.
• Guns have an obnoxious culture to see who can own the biggest, loudest, most expensive, most dangerous, most overkill piece of shit, where you're seen as some kind of sheltered hippie liberal if you choose not to own one. Anyone who barely knows how to use one can own one, and– wait, sorry, that's also cars again.
• I could go on about their infrastructure being an accessibility nightmare, being vastly more expensive, bankrupting cities, disadvantaging people in the inner cities who have to subsidize the car-centric suburbs and deal with their traffic, and so on, but I'm sure I have a character limit.

By the way, "guns are made for killing" can just as easily be warped into "guns are made for self-protection", and suddenly you can compare if their utility outweighs their ease of access and rampant deregulation – just like you can with cars.