For quite a few, it is a _main_ goal for the speakers to either draw attention to their company's product or to provide an air of thought leadership on behalf of their company.
But trying going to a conference that isn't organised by a company, or as a venue for companies to show their products. They exist. They are usually associated with open source groups/meetups of some kind. In some ways they are very vanilla - no fancy food or hotels, nobody actually pays for that crap out of their own pocket.
But the talks - the talks are from a different world. Nobody is there to talk about their company. It's engineers talking to other engineers. Some are serious, some are playful, some are seriously nuts, but all know they are talking to their peers and are not game to spout too much bullshit. If they don't believe it, it doesn't get said. It's like comparing the comments on HN to the journalistic output on a mass media site.