that if acquisition of territory by force had in fact become illegal then all instances of it should be widely condemned and not recognized. That, however is not what we find. Since the adoption of the UN charter in 1945 there have been approximately 18 cases of acquisition of territory by force, most of which (excepting Israel of course) have not been widely condemned. Apart from Israel and Iraq/Kuwait the the results of acquisition of territory by force have been by and large accepted, either officially or defacto. For example: Morroco/West Sahara, South Africa/Namibia,Indonesia/East Timor, India/Goa, China/Tibet, N. Vietnam/S.Vietnam, Jordan/Palestine, China/India, Iran/UAR, Libya/Chad, and a number of other cases. Then you have cases where an occupier defacto controls a nominally independent state such as Syria/Lebanon. Turkey, of course, has been occupying N Cypress since 1974 (after kicking out every last Greek), nearly as long as Israel has occupied the W. Bank, and in spite of this, it was accepted to the EU. Valid law may not be discriminatory. International law in particular, relies on norms for its validity, and as we can see, refusal to recognize acquisition of territory by force has by no means been the norm since 1945.
Second rocket fired from Gaza explodes inside Strip (Haaretz)
from the article: The prophetic lesson of Stephen Hawking's Israel boycott