The pros vs cons. There are more pros then there are cons, especially in third world countries where proteins are not easy to come across and the use of putting vaccines in foods and sending them to countries that are more poor and need the vaccines but cannot afford them.
This isn't really a yes or no question. Some GM products are of benefit and some are not. Genetic engineering is a science that can help or harm.
For example, all tomatoes and most vegetables have a gene that promotes premature rotting. In India a third of produce perishes before it reaches market due to a lack of refrigeration. A company deleted the gene that promotes rotting and as a result it lasts for 3 months without rotting outside of refrigeration. Nothing new was added so it's completely safe and it's obviously beneficial. The consequence is that it is more difficult to save the seeds since you have to ferment the tomatoes to properly save seeds, but it's not impossible.
Another example: Organic farmers graft tomato plants on potato stems, but the problem is that they have to constantly check the growths to prevent potato leaves. If the potato was genetically altered to grow tomato stems that would be safe for certain because they are in the same family and would provide an obvious benefit.
Now, there are other examples that are NOT safe. For example, Starlink corn. It was never fit for human consumption designed as an animal feed, but cross pollination caused it to enter the food supply and children died. This issue directly led to Europe passing strict control laws, but in the united states those efforts went away.
Then there are the crops that produce pesticides. That is a real problem. Tests show that they do enter your blood and cannot be washed off.
See? There are examples of positive and negative applications of genetic engineering.
I myself am studying to be a genetic engineer (focused on human gene therapy, not food) and even I tend to buy certified organic though because without labels I cannot make an informed decision. I would like to see something like QC codes used as labels on all foods, GM and otherwise, that allow people to see at a glance what is in it and all health warnings. That way I could actually compare two different GM foods and be capable of deciding if it is safe or not. The industry really needs to adopt this themselves though because the longer they put it off the larger the public backlash will become. In fact, this very question outlines the real problem: People think that all GM foods are safe or all are dangerous. It's never that simple.
I'm sure there are some modifications that could be considered as a negative consequence to society; but I think more often than not genetically modified food can have more positive consequences. For example modifying a plant to increase crop yield can result in more availability of food and decreased cost for consumer; I think, from what I am familiar with, this can be done without even changing the genetic code of the food, just the plant. Another good use of genetically modifying food is adding specific nutrients a population generally lacks, like they did with rice.
You say it increases crop yield. But it does not matter if people cannot afford it. There is more than enough food in this world already, creating more food does not put it in people's mouths.
And the idea that it lowers the cost of the food is ridiculous. How are the price of foods decided? No by any rational system, but by a completely irrational system called the market. And the market is easily controlled by people that can profit the most off its changes.
Nuclear power was supposed to provide massive amounts of cheap energy to our homes, and no household has ever seen their bills reduced.
GMO foods create larger crop yields by increasing size, pesticide resistance, etc. In theory, the larger crops could be utilized to address fundamental problems such as poverty. But the cause of poverty isn't production, its distribution. Without fundamental changes to the socio-political-economic structures (maybe the eradication of capitalism), the potential for GMO foods to benefit society are stunted.
Another reason why GMO's are not a benefit are because the crops are not practical for all. GMO's crops are patented and expensive - violations of patents carry significant legal penalties. Farmers have to continue re-buying seeds to evade legal troubles - plainly motivated by corporate greed. GMO's require large inputs of fertilizer, which are also very expensive. In short, GMO's are wasteful, and unsustainable.