Many contemporary linguistics scholars subscribe to the theory of multiple Englishes, in that there is no one standard "good" spoken English. Just as there are many regional accents just in the United States, not to mention the United Kingdom and other Anglophone communities worldwide, there are many academically recognized forms of English with their individual conventions.
As for written English, however, there are certain codified rules for various applications. Academic writing is held to a more rigid standard than text messages, for example, and for good reason. Context matters because your writing will be judged by your audience. If your audience is an informal internet forum of peers, lolspeak is considered normal and acceptable because it's understood that everyone there is familiar with jargon and slang terms and they're having a lighthearted interaction. However, if you're sending an email to your boss, there's a good chance you will be perceived as unprofessional if you write "plz send teh codez" rather than using conventional spelling.
You will be judged by your use of language regardless, so just make informed choices.
Lack of consistency is mainly a problem in any writing because it causes confusion. An internally consistent system still works even if it differs from the "standard", in the sense that people understand that "plz" and "please" mean the same thing, but only if everyone uses "plz" and not random variants like "pleez" or "pllz". As long as the lolspeak users are internally consistent, there's no reason why it can't be considered "good" meaning a functional communication system.