Not quite, I have to beg you differ. In your example you are deleting Group 2 and therefore groups 3 - 6 are deleted as well. This makes sense and would work as intended, if it weren't for the fact that group 1 would be delete as well, and all other parent groups!
To give you a better idea, here's my example:
Group A
--Group 1A
--Group 2A
---Group 1-2A
Group B
Group C
--Group 1C
--Group 2C
Now, if I were to delete Group 1-2A, Group 1A and Group 2A, ALL Groups (B, C, 1C, and 2C) are deleted as well!!!