Hi rvpup! Welcome to the group.

While they're not the ONLY gay hostels (called "hostales" in Spanish) in Madrid,
Hostal Sonsoles &
Hostal Odesa are the only ones with websites. There was another, Hostal Puerta del Sol (located, of course, on the Puerta del Sol) was another hostel which catered to gay clientele.
I haven't received feedback about any of these, but if you happen to choose one of them please return to this/your thread and fill us in!

Have a great time in Madrid and Spain!
Saludos, MadridMan
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