Simple answer: It isn’t “INCUMBENT” on anyone to donate to any organization/tzedakah. The only contributions that are every required are (1) on Purim, l’chol posheit yado, (2) obligations that you contractually agree to (shul membership, school tuition, ect.), and (3)in the time when we had organized Kehillos, you were halachicly bound to pay taxes to the kehillah to maintain local schools, shuls, mikvaos, and tzedakah institutions.
No one is obligated to donate to infertility organizations, school tuition funds, tomchei shabbos, or any other worthy tzedakah. The minhag is to set aside 10-20% of your net income for tzedakah, but you have full discretion about where you wish to give that money. Give it to whichever organizations you feel are most deserving of the help.
Of course, you should keep in mind that the halacha does set a list of priorities for distributing your available tzedakah money (priorities, which unfortunately many people seem to ignore to the detriment of local genuinely poor people and local institutions and to the benefit of more “flashy” tzedakos).