The term "enclave strategy" comes from counterinsurgency warfare. For a time in Viet Nam the US tried to establish fortified village enclaves supposedly able to resist the destructive activities and propaganda efforts of the Viet Cong. Presumably the enclaves were supposed to gradually spread their influence.
The phrase echoes Max Weber's advice that to avoid the inexorable iron cage of instrumental means-end rationality and its grey bureaucratic state, we seek out those areas of life that still offer some richer humane culture, during the short time we have while they still last.
Perhaps also we should hear an echo of Descartes's desire to find the ultimate enclave in the self-certainty of the self, a fortress from which certainty can be spread out over the countryside of belief, restructuring as it goes. But, of course, Descartes's strategy has been deemed by many to have contributed to the spread of that instrumental rationality that Weber and Kwinter fear.