I have a theory for why developers complain it is too low. A large recurring “donation” can be a bit of a trap.
In practice it can be an hidden freelancing or employment relationship.
Donators actually expect you to do things in return, for example with cURL they expect the developer to do security fixes.
Otherwise they will not get the “donation” the next month
It may not be written on a paper for legal reasons, but it is made for a good reason.
A true donation you do not expect for anything in return.
This could explain why they consider donation too low. A gift cannot be too small. But a gift where the giver has very high expectations in return may be too low.
In practice it can be an hidden freelancing or employment relationship.
Donators actually expect you to do things in return, for example with cURL they expect the developer to do security fixes.
Otherwise they will not get the “donation” the next month
It may not be written on a paper for legal reasons, but it is made for a good reason.
A true donation you do not expect for anything in return.
This could explain why they consider donation too low. A gift cannot be too small. But a gift where the giver has very high expectations in return may be too low.