Nobody ever actively pushed for incorporation of Transjordan into Israel AFAIK (I may be completely wrong here by correct me if I am) in spite of that being a core agenda of Jabotinsky. Irgun weren't anti anything at it's core so to speak. The same narrative has influenced general pop culture depiction of Irgun I guess. Post formation of Israel, Irgun and especially Begin were villified and demonized by Israeli left. But within a year Hagannah would also pick up the same line. Yes, when they dropped said restraint the one sided savagery did turn into a gang war with horrific collateral damage. Half of Irgun had already left for rejoining back to Hagannah before Jabotinsky could even get a hold on the organization.

Existing for a span of nearly two decades, the organization went through multiple transformations. Even after Arabs went ballistic in '36, Jabotinsky advised restraint until '37 when things became unbearable. Click to expand.It took Irgun six years to give up restraint.