WHO this is only a suggestion, the specific how to operate, or to countries to take their own ideas.
Now this advice to countries to open the door, from the perspective of the global economy to consider things, rather than from the perspective of the epidemic to consider things. That is to say, WHO is also a part of the international economic life, so there is no way to avoid the influence of economic factors when considering things. That is, it's a matter of which route the WHO takes to fight the epidemic.
The world can't come to a halt because of a pandemic; the world's 7 billion people have to keep on living. But it's clear that the travel restriction policies enforced by countries are having the biggest impact on the economy, and while the rich countries with thicker bottoms may just be living uncomfortably, the poorer countries are going to have an economic crisis under such travel restrictions.
The WHO is an international organization, so of course it thinks globally, it doesn't take into account the specifics of each country. WHO is likely to find that the worldwide losses caused by travel restrictions are higher than the losses caused by the epidemic itself through mathematical modeling, and will naturally choose the option that causes the least harm to the global economy. As for the countries and individuals who are adversely affected by the opening of national gates, they are contributing to the world! Sacrificing the local to satisfy the whole!
But when countries think about things from their own point of view, they don't want to be the ones to suffer, they want to be the ones to make a profit. So when it comes to this proposal, each country has to consider things from its own conditions, and it can't sacrifice itself to make the world a better place. It is important to realize that a government is only the government of one country, not the government of the world, and it has to work for the well-being of its own nationals, not for the well-being of the people of the world.
So, the final result can be expected, the countries that feel they can make a profit from the WHO's proposal will naturally welcome it warmly, and those that feel they will be "screwed" by the WHO's proposal can of course ignore it, because the government has to serve its own nationals first and foremost!