I haven't had time to read the plethora of complaints about glue, but I will state one very good reason for using it:
glue distributes forces much more evenly over the entire area of adhesion, versus a screw, which concentrates forces in a very small area. What this means roughly, is that you can manage larger forces and impacts by quickly spreading them out. For example if you superglued the tips of your fingers together, you'd still be able to 'wiggle & pry' your way out of it, perhaps at the expense of your skin. If you glued both your palms together, there would be no way you could separate them under your own power, without a solvent.
And speaking of solvents, perhaps Apple uses an in-house solvent to manage their adhesives. So, people wanting to figure out how to pry off their batteries are better of(f) *edit* discovering the formula to the appropriate solvent, not complaining. That's like complaining that you don't have the proper screwdriver when a company uses a proprietary screw head.