Capitalism mainly destroys culture through two different avenues
First of all, it destroys what we now call folk -or "people's"- culture. Man used to have a lot of his time devoted in creating the things that made life enjoyable: poetry, music, games, tales, even the mythology and religion he used to explain the world around him. He was also a participant in its survival and circulation, forming a common heritage whom he shared with his fellow man, passing down his knowledge and traditions from father to son, mother to daughter, etc.
Now he isn't nearly as capable of such as he no longer has the time or the energy. Half his waking hours -or even more- are spent generating profit for someone else, while his children are taught how to "sell themselves" to their future employers, or "finding their own brand".
He can no longer participate in the creation and maintenance of culture with his community either as he now also finds himself atomized in these little privatized spaces called Suburbia.
Furthermore, what ends up filling the void is not culture as naturally emerging from humans like before, but through this Culture Industry. What I mean by this is that Culture itself is subjected to a division of labor where certain people, mostly those working in the media industry, have the specific jobs to produce culture, not to create it.
Culture is now subjected to the rigorous logic of the assembly line. It is there to generate profit, to minimize cost and maximize revenue through appealing to the lowest common denominator consisting of the now desensitized people. Worse still, whom it generates profit for and is accountable only to are the shareholders and the owners, which in spite of owning nearly 90% of American media through a series of conglomerates, only seem ever more intent in increasing the size of their coffers.
What results is the consumerist culture, the homogeneous throwaway culture that spreads like cancer throughout the Globe in this epoch of Neoliberalism and mass media, only to be replaced by yet another manufactured fad after it inevitably burns out from the saturation.
There are two issues with your arguments. Firstly, regarding cultural development and individual manifestation. Most people fall apart unless they have a job or some sort of an activity to keep them preoccupied and have a sense of value to society and this isn't achieved proactively where the individual takes initiative. A very small percentage of extraordinary, conscientious and talented individuals manage to busy themselves without an outside need; It's human psychology. There's a a reason why people have mental breakdowns when they're fired and fail to find a job / activity that would make them feel valuable to society.
Regarding your "It's all for malicious profit and exploitation of the poor". The free market adapts to the most efficient and effective way of maintaining itself resulting in technological and cultural progress. Furthermore, it has inadvertently become the best vessel for globalization, human progress and unification. Socialism has been tried and failed all through out history and its ideas are the anathema of what you people fight for.