https://www.roadandtrack.com/new-cars/videos/a5238/watch-the...
To really answer your question, I've arbitrarily picked a few common vehicles with metal roofs.
The IIHS says the Civic roof withstands 13,195lbs of force: https://www.iihs.org/ratings/vehicle/honda/civic-2-door-coup...
A Subaru Outback: 18,533lbs of roof strength: https://www.iihs.org/ratings/vehicle/subaru/outback-4-door-w...
A BMW 3 series has roughly the same roof strength as a Model 3: https://www.iihs.org/ratings/vehicle/bmw/3-series-4-door-sed...
An Audi A5 is only 16,327lbs of roof strength: https://www.iihs.org/ratings/vehicle/audi/a5-coupe-2-door-co...
You get the idea!
Having very strong pillars is pretty much a prerequisite for surviving a rollover in an EV.
That isn't as big of a difference as I'd have expected.
The Tesla Model 3 is 3552-4072 lbs, while the new Jeep Wrangler (JL) is 3955-4455 lbs.
I could compare it to a miata that is ~2300lbs. But that's not really relevant then, is it? A Jeep Wrangler is basically a truck - so I don't think that's a good comparison.
Compared to other "compact executive cars" (as its class states) it's close to the competition.
The vibe I've got from talking to people is that they think the Model 3 (or Teslas in general) are significantly heavy relative to normal consumer vehicles. It's pretty surprising to them that even a 2 door Jeep Wrangler is actually heavier.
Same with my 1-series. It's obscenely heavy for how small it is.
A more spacious Alto that uses some aluminium and magnesium is around 650kg.
Talking about "not-so-heavy" cars...
That's a Pakistan-only car with no safety features [0]. (From the Wikipedia description, "a car with everything manually operated, and with no safety features. The car lacks airbags, ABS, rear window defogger, side air conditioner vents, seat belt reminder and even rear seat belts.") So yes, it's light. You'll also immediately die in a collision, but you get what you pay for I suppose. (The Alto is sold more broadly, but it's still obsolete)
Not exactly comparing like to like.