Is an open source project obliged to provide support for its users?
Certainly NOT. From GPLv2:
no warranty
11. because the program is licensed free of charge, there is no warranty for the program, to the extent permitted by applicable law. except when otherwise stated in writing the copyright holders and/or other parties provide the program "as is" without warranty of any kind, either expressed or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. the entire risk as to the quality and performance of the program is with you. should the program prove defective, you assume the cost of all necessary servicing, repair or correction.
The rest is all about goodwill of developers and active users. That means you.
A LISP programmer knows the value of everything, but the cost of nothing. -- Alan Perlis