Neither Lion nor Ethiopian had stellar safety records, e.g.
* https://www.nytimes.com/2018/11/22/world/asia/lion-air-crash...
* https://en.wikipedia.org/wiki/Ethiopian_Airlines_accidents_a...
The training hours should also be looked in the context of the total hours flown on that specific model - a pilot who just sat through the short training session would have a different perspective than a pilot who sat through the same training session but has also flown the plane for hundreds of hours.
It's also not a brand new airplane - it's a modification of 737, so the training is transitional. It's not like Boeing took a freshly minted Cessna 152 pilot, gave them a 2-hour seminar, and type-rated them for the 737 Max.