Well when talking about a MNC and Global economy, and practices of said MNC's it gets really complicated. I can write pages beyond pages about the pros and cons, what good an MNC can do for a LDC and what bad things may come to a LCD.
Other thing you have to look at is different schools of ethical reasoning. Say if you open a large Textile factory(with assumption that it practices safe working conditions), this Textile factory employees 500 people, these 500 people wouldn't have job if it wasn't for this factory. The factory allows a 500 people to feed their family with maybe 10% variance for those whom have multiple people from same household working in the plant. However the byproduct from your factory releases pollutants in the river, that is at the legal level of pollution but it may cause health issues for town 10,000 people down stream. Do you close the factory laying off 500 people to stop polluting, or do you keep it open. If take an Utilitarianism ethical approach you do what is good for largest amount of people, so you close the factory, 500 are unemployed but you no longer have to worry about degrading anyone's health. Now if you take same ethical approach say for an AIDs vaccine that cure 90% of people completely but 10% peoples organs will implode killing them due to a side effect. an Utilitarianism approach would say that's okay because more people benefit than will die from it.
I know I'm not doing a very good job of explaining practices of MNCs, but im trying to explain that , its hard to do anything, especially in a fragile as economy as LDC, that won't do any harm to someone.
Even something of simple giving aid to a country can have negative effects. If you donate tons of rice to a country that is having trouble feeding it population, you are than undermining the farmers who are growing rice, now they are forced to sell their crop at much lower price. There isn't even a guarantee that rice you donated to a country will even ended up in hands of those who need it the most, its not uncommon at all to see people selling bags and bags of UN marked rice that says right on bag (Not for sale, for aid purposes only). Same thing goes for donating clothes, why would you go to local weaver to buy clothes, when you can buy used clothing donated by Americans for fraction of the price.
As to why I want to work for MNC, is because I love to have job that allows me to travel abroad and work with other cultures. I love learning about other cultures, and learning about their culture. Just because I'm working for MNC, doesn't mean im going be inherently evil, that going be doing corrupt things that only damage people lives for the sake of profits. I'm not going punt starvin marvin into a ditch a because hes in the way of a construction site. I want to do what is ethical and good for people, I want to improve the lives as many people as I can, there is just not always a clear cut solution, sometimes even when trying to do good people get hurt. I hope that answers your question. I am still a very long ways from every getting job related to my degree, I still have to get my MBA, and than find a specialized field and get my certifications in it. I am no expert in the global economy so please take everything I said with a grain of salt, I just have some general knowledge about various LDC and MNC operations from all the research papers I had to write in the past.