That’s not the impression I have (never used one myself). Yes, some people really like them and argue that they are worth more than what they paid. Maybe they got a lucky and got a good one (quality seems to vary considerably, which is expected at this price point) and/or just connect to the instrument in a way that is often hard to predict. But a much more common opinion seems to be that they’re surprisingly usable for the price, but still a significant step below more established budget brands like Squier or Harley Benton.
If Glarry charged 50% more, they would still be comparatively cheap, but the difference between them and other budget brands would be smaller, and people would be more likely to pay the extra cash for a brand with a better reputation. That’s probably a very significant factor in why they’re priced the way they are.
Also consider that the posts of the people who really like them probably don’t represent the experience of the average buyer. If someone buys a really good bass for $100, they’re much more likely to tell everyone about it than if they bought a bass for the same price and it was just what they expected, or even if it was trash, because that’s a calculated risk if you buy an extremely cheap instrument. So you’re likely reading about the experiences of a heavily biased sample of owners of these basses.