Do the Religious commandments and laws become null and void, if they are not even followed by the ones who set them?

Not necessarily.

They started that way if they are derived from belief in some deity...

Obviously not. Religion sets forth an ideal, an ideal to be striven for that is often difficult and even sometimes impossible to achieve. It's the striving that leads to betterment, and religiously speaking, failure doesn't happen when the commandments and laws are broken but only when one gives up on trying to keep them.

They are null and void since they are part of an unfounded, unproven, ridiculous, bronze-age Cult Book.  The Christian followers happen to ignore most of what Christ taught in the New Testament - so it's already a cult of complete hypocrisy.