Consent vs Informed consent

I was chatting with someone a couple of days ago, about how investment banks actively induced home mortgage sellers to actively push loans to people who could not afford them at high interest rates during the financial bubble of the 2000s.

He came back with an interesting argument that he did not have an issue with what was done as long as it was done between consenting parties. If an adult gave his or her consent and signed on the dotted line, then that person was liable for what followed. The people who bought these loans were also greedy - buying homes much bigger than they knew they could afford.

I do wonder however, if all the fund managers who were investing retirement savings of senior citizens understood the complexity of the derivatives they were buying. This is not very different from the scenes in the old Hindi movies of the 60s and 70s where the zamindar obtained the thumbprint of the illiterate farmer on a stamp paper and the farmer only figured out later that he had lost all he had.

I have been wondering if the law needs to make a distinction between consent and informed consent.