The important thing to note about the stats provided in the OP is that all of them directly increase DPS. The argument could be made that Stam increases DPS by helping to ensure that the warlock does not die, however, this thread is designed to discuss maximizing DPS, not survivability. DPS and survivability and not often direct tied to each other as most damage is avoidable, and therefore the focus while moving out of/avoiding/interrupting said avoidable damage remains on maximizing DPS. For questions on survivability, the Warlock Mechanics thread is a better venue.
The only legitimate argument that can be made in Stam's favor is that more Stam = bigger Life Taps = fewer Life Taps = fewer GCDs used on LT. However, due to the mandatory
Glyph of Life Tap, the gain is minimal, and is worth far less per point than any other caster stat. Stam should never be a stat that a warlock worries about.