Why is foreign direct investment so much more controversial than foreign portfolio investment? How does this relate

Question:

Why is foreign direct investment so much more controversial than foreign portfolio investment? How does this relate to Mexico in the 1990s?

Portfolio
A portfolio is a grouping of financial assets such as stocks, bonds, commodities, currencies and cash equivalents, as well as their fund counterparts, including mutual, exchange-traded and closed funds. A portfolio can also consist of non-publicly...