Comparing the two is like comparing apples and oranges, and you'll just Alienate people. I'm not entirely sure how it would even be possible to make traveling across for anonymous donation illegal. When we travel we follow the laws of the country we're in. Saying this, I don't disagree with you about anonymous sperm donation being unethical.
My husband is infertile and we'll need to use a donor. We've spent almost 2 years delving deep to find as much information as we can because like most parents, we want to make sure we maximise the chances of good outcomes for any children we have.
The majority of studies, and the majority of donor conceived children say that a known donor is the optimal route because donor conceived children have better outcomes if they can access their genetic mirrors, their medical history and where possible their donor/donors relatives to maintain biological links and answer questions as they come up. Obviously this can't always happen, and lots of places like the UK do make information and the option of contact accessible from when a child turns 18.
For what it's worth, I personally think it's unethical, and cruel for a parent using a donor to actively prevent a child from accessing basic information about themselves. I think the bare minimum should be open ID once the child turns 18.
However while I do hold these views
The much bigger issue is the lack of donor regulation in some countries. Lots of countries have absolutely zero limits on how many families a person can donate to. In the UK a donor can donate to a maximum of 10 families. Donor's also lose anonymity when the child is 18.
In the USA on the other hand, there is no limit to how many families a man can donate to, and a donor can remain completely anonymous. This opens up the potential for issues such as accidental incest. There have been stories where men haven't been told that their donations will be split into multiple "straws". So one donation can be split into 4-8 straws. There was one man who has fathered something like 90 children due to the unethical and unregulated practices. I personally feel there should be an international regulation of how many families a man can donate to via a clinic. It's something that should be the same across the board for ethical and safety reasons. Obviously it wouldn't prevent out of clinic donations but it would be a start in addressing major issues in the donation industry.
And no, I don't feel like any of this is anything like FGM.
Apologies for the huge essay. Like I said, this has been our journey for the past two years, so I have done and still do a lot of reading and research