There are substantial externalities to commercializing products that cannot be repaired. Fantastic amounts of non-biodegradable waste, overconsumption of nonrenewable material resources, and of course financial loss to consumers and opportunity cost to the secondary market. "Just choose not to buy the product" is only sensible if choosing not to buy the product fully insulates you from the effects of its existence.

Regulation places the cost of those externalities and/or the responsibility to prevent them back in the lap of the manufacturer.