Green is only good at one thing: Playing creatures and turning them sideways. Red can use burn spells to kill them. Black can use hand discard to force you to get rid of them before you can play them, or use Doom-Blade effects. White can tap them down so they can't attack. Blue can counter them on the stack or bounce them. All of the colors have access to removal. Green does as well, but green's answer to a big creature is generally "play a bigger creature".

While green does have decent artifact/enchantment removal, it doesn't really matter, because, for the most part, you use creatures to win (unless you're playing Vintage or something that lets you go back to the old days when spells were significantly better than creatures, but for modern Magic, creatures are what wins you games). I'll also point out that every color removes something. Black has the best creature removal. Red has the best land removal. Green has the best artifact removal. White has the best enchantment removal. Blue has.... well, okay, blue doesn't really have much, but it has counterspells, card-drawing, and extra turns, so it's plenty broken without any removal.

Green has mana ramp? Really? Where? I don't see it. Yeah, there are creatures that have Llanowar Elves type effects, but that isn't really worth it, because it just takes 1 damage to kill it. It's not like, say, Dark Ritual, where you just flat-out GET the mana. And you mention black has the mana ramp as well, but I honestly think that red has the most ramp in that regard (Inner Fire, Desperate Ritual, Mana Geyser, Seething Song, Infernal Plunge, Braid of Fire, Treasonous Ogre, Battle Hymn, Geosurge, Rite of Flame, Pyretic Ritual, Soulbright Flamekin). The difference is that red only gets the mana for a little while, which is in flavor for red being a "act first, think later" color.

I'll also point out that green's "You may play an additional land this turn" effects are worse than blue's "take an extra turn after this one" effects, which give you another land drop, plus giving you another combat phase, the ability to untap everything, another planeswalker ability, and the ability to draw a card too.

Now, then, you want to talk philosophy? Okay, let's talk philosophy.

• Selfish actions have caused people to take advantage of other people. That's proof that not following white's philosophy causes problems.
• There are plenty of stupid people out there that get hurt because they don't know better. That's proof that not following blue's philosophy causes problems.
• People will take advantage of you if you don't learn to exploit them first. That's proof that not following black's philosophy causes problems.
• Governments can control people to a very unsettling degree when they don't allow freedom. That's proof that not following red's philosophy causes problems.
• If you don't respect nature, you won't have a good place to live. That's proof that not following green's philosophy causes problems.

See how all of the colors have, in some way or another, a point? Green's philosophy is perfectly valid, yes, but no more so than any of the others.