I agree, though I think there's an irony in the mutual incompatibility of many FOSS licenses. For instance, try making a GPL project that depends on a data file

I agree, though I think there's an irony in the mutual incompatibility of many FOSS licenses. For instance, try making a GPL project that depends on a data file licensed under Creative Commons. One's best bet in such a situation is to ask the rights holder to release to you under a compatible license, but people (and institutions) are generally reluctant to do so. Two permissive licenses, one headache for the FOSS dev.