Why is the belt material slightly elastic?

It is intentionally designed to be slightly elastic. The belt only allows a small amount of stretch, enough to be comfortable. Never sags strong thick stretch material. It's a perfect combination of stretch and firmness.

Why can't the buckle slide through standard belt loops?

It is to prevent the equipment you wear from falling off while using the toilet. The belt will fit through your belt loops but the buckle will not, however you can easily take the buckle off and put it back on after you have looped it through.

For a 42” waist which is better the 36”-42” or the 42”-46”?

The full length of the Medium-for Waist 36”-42” is 49”. There is a length of 7 inches that can allow your tail to leak out, so you can choose a Medium-for Waist 36”-42”.

Who is suitable for using this tactical belt?

The tactical belt suits for military, SWAT, fire fighters, worker, sporter and other outdoorsman. Anyone who do physical activities for a long period of hours will get a great use out of the belt.