None of these websites offer free "bitcoins". They offer free fractions of bitcoins, essentially worthless. Bitcoins means more than one bitcoin, and to make more than bitcoin on these websites would take weeks.
I would suggest that "bitcoins" refers to any amount of the stuff... saying "0.001 bitcoins" is just as valid as saying "10 bitcoins" or "twenty one million bitcoins".
As to your other point I have a standard response to that:
What good is it if one only gets very very small amounts?
https://bitcointalk.org/index.php?topic=74046.msg1088930#msg1088930
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