Sorry, but the impression I got from your post was that you objected to the concept of ESL classes and didn’t see why they were necessary, since you yourself used other means for learning languages.
The fact is that they are an excellent tool. You sound like an educated person, you are probably not a hotel maid, and you probably have the time and space to devote to finding and using the on-line or other tools to learn a language for leisure purposes.
But if you come here from another country, need to learn to speak the language of this country correctly or at least as competently as possible in a short time, while you are simultaneously working and attempting to fend for yourself in the new language, there is no substitute for classes and human contact. The latter also gives immigrants assistance in assimilation and a behavior model for life in their new country. Much of the work of an ESL teacher is cultural, and this is a challenge because the students will not all themselves come from the same native cultures - but they all need to understand and adapt to ours.
When speakers get to a higher level and are more comfortable with our culture, they may want to use other tools. But ESL classes are a fast and traditional tool for immigrants to the US who want to gain rapid fluency and understanding of our world, and I don’t see why you should dismiss them with the haughty assurance that these people could just go out and buy themselves some CDs. You’re approaching the matter from an entirely different point of view. Every dime we spend on ESL is well spent.