I have done the Soudet, Petit Ballon and Platzerwasel so I reckon I'm in some kind of a position to give my opinion.
1. the Laruns stage has the Soudet, which is essentially a 10.3K - 8% affair = 32-33 minutes of climbing. The 10K before the actual climb are 3.5%, and that's the only reason they put the HC sticker on. After the descent there is some flat parts, a 4K 6.5% cat. 3 climb, and Cambasque is 8.5K at 8% with the steepest parts in the end (another 30 minute slog) before there is 18K of downhill / flat to the finish.
2. Today's stage has Petit Ballon, which is essentially a 9.5K 8% affair (notice the similarities with Soudet). While the Soudet has 10K before at 3.5%, if we compare those relatively easy kms of Soudet with what is before Petit Ballon (3 Cat 2 climbs), today's stage has a much harder start (or if we compare Soudet / Cambasque with Petit Ballon / Platzerwasel, all the Laruns stage had was a Cat. 3 climb while this stage has 3 more Cat. 2 climbs). After the descent of Petit Ballon (bad asphalt, many holes), it is immediately up Platzerwasel (so only 10 minutes of 'rest'), which is 7K at 8.2%. After the official col, there are 2.5K at 4% with 1K at 8%, a flat bit in between and another K at 6% (this part = Breitfirst = a cat 4 on it's own, but uncategorized this Tour). So albeit the Platzerwasel seems to be a bit easier than Cambasque, there are still some hard sections after the official climb (similar to the Cambasque, it's a approx. 30 minute climb to the Breitfirst), and there is no recuperation whatsoever with only 6K to go to the finish (slight downhill, but some rolling terrain).
So yes, this stage is harder as it's having 2 30 minute climbs back-to-back before the finish, while the Laruns stage had time in between the 2 hardest climbs which were also 30 minute affairs (e.g. 30-35 minutes between the top of the Soudet and the base of the Cat. 3 clim) + 3x longer descent / flat to the finish.
But you know what? Don't take my word for it: Ride both stages and come back to me with your experiences.
And if you're still not convinved, ask any rider in this Tour after the finish and I'll happily place bets on what they would answer.
I know some of those riders, I hope you do as well.