Style
To say that there are no rules in language because language itself is intuitive is a bit like saying that there is no need for table manners because eating is a basic instinct. It is a truism that grammar, spelling and punctuation rules are only loose conventions - but it is a truism that can be applied to criminal law, too. We do not follow social and moral conventions because they are immutable laws of the Universe, but because they make our lives easier, safer, more pleasurable etc.
The primary purpose of language, think the poets what they may, is communication; language that is uncommunicative is worse than worthless, as it shows the most profound contempt for its audience and thus for the human experience itself. And the best, most reliable and probably easiest way of making language communicative is to follow some basic conventions that are agreed upon through a process of academic peer review: slow, impersonal, wide ranging.
But what about Joyce, you ask? What about e.e. cummings? They threw away the rule book and achieved transcendent beauty. Well, much as this may come a shock to you, you are neither. And there is a 99.9% chance that if you just throw words onto the page you will end up not with a William Carlos Williams or an Ezra Pound, but with T. Rash. To earn the right to throw the rule book away, you need to have had it firmly in hand first. Just as the greatest modernist and abstract artists - from Picasso to Pollock - were all accomplished students of the classical arts of drawing, perspective, oil painting etc., so does the aspiring writer start not by flicking paint on the canvas, but by patiently going through the love labour of learning his craft.
Writing is not an artistic outlet for the lazy. Like anything of quality - from a good cup of tea upwards - it requires application, determination and drudgery. The process itself of becoming a writer is much the same, a steep learning curve trudging over many a Harvard style manual and Oxford thesaurus.
Grammar
A studied departure from convention is an intellectual act. Simple lawlessness is a destructive one. A dangling participle that was left high and dry due to raw ignorance is a very different animal to an infinitive artfully split.
Punk music gloried in the lack of musicianship of its heroes - but it also frankly admitted its own anarchic, negativist agenda. It was not originally what it later became - an art form that hid its practitioners' basic lack of application behind a wall of manifesto. Just as there is nothing glorious, revolutionary or particularly artistic about a musician who cannot play his chosen instrument, there is nothing innovative and liberated about a writer or poet who are not familiar with what's out there in terms of stylistic and grammatical technique. To me they will always seem ignorant and lazy.
Context
To write is not just to use language, it is to use the best language as appropriate. It's all very well to say: look around you, adapt yourself to your environment, write in a language that is comprehensible and acceptable to the people you are addressing. But how to achieve this mastery of context? Not, I think, through trial-and-error bumbling. Language that is good enough to be written is good enough to be learned, and that is as much true of l33t as it is of the most refined Shakespearean prose. I can't understand l33t because I never learned it - and it would be foolish and arrogant of me to try and pass off my novice attempt at it as worthy of attention.
There are very few great writers who were truly uneducated people. The spark of originality that distinguishes great prose or world class poetry from a piece of adolescent homework is in part raw talent - but it is also largely an understanding, gained through extensive reading of contemporary and classical works, of what is missing in the language of the day.
If you want to write, you're going to have to read. And you won't do yourself any harm reading a few books that attempt to set out some helpful guidelines. You don't need to follow them slavishly, and you shouldn't confine yourself to grammars or style manuals, but by all means explore and expand you mind; read about music and harmonics, semantics and semiotics. Originality and innovation never come from ignorance, and concomitantly ignorance is not originality. Sometimes, when people say something like "a child could have done this", they're right - a child really could. And it wouldn't have been good art then, either.