In my opinion, the problem is less about the actual hangboarding, and more about beginners not knowing when to stop and let their fingers rest. Since new climbers aren't usually used to the strain that climbing puts on their fingers and tendons, it's very easy to overtrain and to get injured.
This is true just by climbing alone. Add to that the element of hangboarding and you are in a very high risk of injury!

If a new climber can listen to their body, and also follow a strict program that will minimize the potential for finger injuries, even including hangboarding in the program could be fine. But, this will take a lot of self discipline that a lot of climbers don't seem to have.

Generally, I think that if you do things correctly, you could be fine doing finger specific training during your first year of climbing.