So, lots of people argue about the existence of God and whatnot and say "he is love", "he is goodness" etc etc.

However, "good" is simply from our morals - there is not necessarily any ultimate good or universal good.

So, for example, good is not a universal constant in the Cosmos.

Passing over this, let us consider the statement below:

"Evil is abundant on Earth. Ergo, this proves that only the Devil exists; for goodness is simply an absence of evil."

How is this any different from similar arguments put forward by religious people.

Now, of course, lots of people want to be "good" and whatnot and "love thy neighbour" - however, this does not serve to disprove the statement above - it does not serve to disprove the existence of the Devil alone. And the existence of Devil does not mean that an opposite of Him also exists.

Ergo, whilst we will all condemn Hitler and say "What an evil man" blah blah; it actually means nothing, no? The entire Abrahamic doctrines could be turned on their head no "Goodness is simply an absence of evil - ergo, only the Devil exists". Such a Devil could be deistic and could simply go about His business having fun, making many worlds, making many bubble universes and so on and so forth - this could not be disproved and neither can it be proven.

And yet, religious people would baulk at the idea and there would be uproar - because it shatters the lovely morality that exists with religion of "goodness" and whatnot. For all you know, the world (or worlds) could be a much colder place than you wish - only the Devil could exist and goodness could actually be an absence of evil. What we think of as "God" could actually be "Devil" who is not "love" and whatnot.

P.S.

I'm sure this makes as much sense as religion, right?

Good is created from your appreciation. Bad is created from your disapproval. It's not the other way around for either.