As to why so many joined, after having spent nearly a decade researching each of the men who served with the 1st Florida Cavalry, Union Volunteers I believe there were a lot of factors that drove that, just as in the rest of the Confederacy from 1863 on. Too many to cover here. Desertion was really quite high in the Confederate army from 1863 until the close of the war. Northwest Florida and south Alabama were not as deeply linked to the slave economy so when the war really became difficult on the battlefield and at home and many well-to-do slave holders were not doing their share by either fighting or feeding soldier's families it wasn't too hard to make a decision to walk. Hunger was particularly rampant in this area during the war; a combination of impressment, Union troops stationed at Barrancas, Confederate troops scattered throughout the area and concentrated in Pollard, AL and the deserter gangs that could hide in the woods and swamps. Going over to the Union meant slightly more consistent pay and for some, the family came with them and stayed in Warrington. And finally, one of the driving reasons was convenience. Unlike most of the other states that had Union regiments, you could stay close to home and not go far to join.
Isaac's father Benjamin is likely related to my Pitts who settled in Holmes County: John C. Pitts and son John Ephraim Pitts. Another researcher of Benjamin and I both think that he and John C. are cousins. John C. served in the 60th Georgia Infantry until shot through the right arm at Fredericksburg. He was sent home to south central Georgia (moved to Holmes county after the war) and was driving cattle up from south Florida to Andersonville when the war ended.