No, it's not. Text speak and internet slang are simply different ways of using the language, and fit the purpose of the medium. for instance, text speak like "l8r" or "2nite" are entirely legitimate in a text because you only have l a limited number of characters to send a message, plus they are quicker to type. A similar situation exists for internet slang like LOL or ROFL, IMHO etc. In internet chat a quick response is needed and abbreviations make this easier. Also, the odd spelling mistake in a conversation on-line does not compromise the information begin transferred.
I frequently use internet chat where I do not check spelling, use abbreviations and insert the odd smiley. I also work in an Office editing work that has to be perfectly spelt and comply with our publishing standards before being uploaded to the web. Text speak is simply another mode of language, and has its place. It's similar to a child speaking to his parents or friends. The way he will say something changes dramatically to use the appropriate style of language. Text is an example of this range of "registers", but in a written format.
BA (hons) in English Language. Look up David Crystal for more.