That's not true at all. All drop tests I've seen have put the 8 under unreasonable strain to cause breakage, because their goal is to break it. It's also been proven to be almost impossible to bend - making your statement completely false. Glass IS more durable than the tin can thickness aluminium backing of the previous iPhones, but it will shatter if you try hard enough. My guess would be that it'll survive about 99% of regular drops that occur from ordinary use. Only in extreme cases will it shatter entirely. Whilst Apple have not claimed to have engineered indestructible glass, the iPhone 8 is definitely built better than the 7.
YouTubers are out for the clicks. Shattered iPhones get clicks. Going with the agenda that the iPhone 8 is weaker because it's made of glass gets clicks. They're not a great source for real world facts. One YouTuber I saw - EverythingApplePro - did everything he could to get the iPhone 8 to break. When it inevitably did, he'd say, "Well, that wasn't as strong as I thought it would be." Having literally gone to great lengths to cause massive damage. It's Fake News.