First of all there are no eyewitness acounts of the execution of a miracle worker called Jesus. In other words the story of his death comes from literature not historical facts
In latin the word crux from which we get crucifixion referred to the gibbet or simple scaffold on which the condemned were hung, it was not defined by its shape. It could be any upright pole with a cross member nailed on the top of the post or no cross member-- or it could be a living tree. The punishment of crucifixion referred to the agonising death incurred, especially if all the weight was on the nailed hands without support from the legs. Either way it was a humiliating, agonising death and a hideous reminder for onlookers to obey the Roman ordinances.
And yes dothemath, the GB are far more likely to highlight anything which furthers their own viewpoint. Religious thought only looks for affirmation of existing beliefs, never does it investigate counter information.
In the past the WT understood that the Christian cross is pagan so they look for ways to downplay any link of their brand of religion with conventional Christianity. These days all that seems to matter is blind obedience to HQ.