"not refunding points below 100 seems to create a problem"
Yes. The point is for whom it creates problems.
1. Normal users usually get quite above 100 in a few months.
2. Normal users usually choose wisely their games and never go CD.
3. In the rare case a normal user goes CD, it happens once or twice, not five times like you did (and maybe he already got 400
![webDiplomacy points D](images/icons/points.png)
).
So. Since Points are NEVER refunded when you lose, unless you got less than 100
![webDiplomacy points D](images/icons/points.png)
AND you didn't CD, I can't see any problem created except for those who belong to none of the categories listed above. The solution is pretty simple: try and do your best to get into one of them. Personally I suggest you to get into category #2. And if you're "just curious of the policy"... well... the policy is just suggesting to you the same.