And while that also has a soft brainwashing effect, it actually adds some information that allows you to make a conscious decission. An ad is just the brainwashing.
Word of mouth is still the best form of advertising though - agreed. That's not to say other forms of advertising aren't effective, or useful for the consumer.
For example, I know what movies are out mainly through billboards. It's useful to me. If one looks interesting, I might look it up on the net and see if I want to go see it. I'm not being 'soft brainwashed', I'm being informed of a new movie I might want to go see.
For a long time now advertisement has been about manipulating people's emotions so that they seek fulfillment in the product being advertised. When was the last time you saw an Apple ad where the purpose was listing the specs so the consumer can make an informed choice?
Every input we receive to our brains could be said to be a soft form of brainwashing.
Good advertising serves a use for consumers. Without it, you wouldn't be aware of what you can buy/do etc. If you want to opt out of that, fine. Personally, I find it invaluable to be aware of what is going on.