De Vries crashed during Friday qualifying for last weekend's Azerbaijan Grand Prix and then suffered another incident in the race when he tapped the inside wall at Turn 5, having to retire with a bent front-left toe link.
The 2020/21 Formula E champion is still chasing his first points finish this season, with fellow rookie Logan Sargeant the only other driver in the same boat as 2023's tight midfield battle has opened up opportunities to sneak into the top 10.
Team boss Tost has defended the Dutchman and made comparisons to previous Faenza alumnus Sebastian Vettel, who also had a propensity for damaging his car in his rookie days before establishing himself as a major force.
"There's, as I always say, a learning process and a crash period," Tost said on Saturday in Baku. "Because if the drivers don't crash, they don't know the limit.
"This is a credit you must give them, otherwise it doesn't work.
"And there was no driver not crashing. I remember that Sebastian in the first races came back the first lap most often without the nose. That's part of the game."
Baku's revamped sprint format with just a single 60-minute practice session ahead of qualifying proved an additional hurdle for rookies, which Tost described as "problematic".
"As I always say, if a rookie is coming to Formula 1, he needs minimum three years to understand what's going on here.
"Look now to this race weekend format here in Baku. We have the free practice one and then you go into the qualifying and what's problematic for young drivers and rookies is to get most out of the track and of the tyres in qualifying, and that's really a difficult exercise.
"What happened [in qualifying] with Nyck was quite clear. He braked a little bit too late because he expected maybe more grip. And then he lost the car."
A disappointed De Vries described his Baku retirement as a "stupid mistake" after being stuck in traffic behind Alfa Romeo's Zhou Guanyu.
"I am very disappointed in myself," he told Viaplay. "It was a really stupid mistake, which is completely my responsibility. I'm really disappointed about it.
"The walls are close and I just got a little too close, that was enough. I was probably getting impatient behind Zhou, because I was stuck there.
"But that doesn't make it right, I still made the mistake and that shouldn't happen."
