I do not disagree about how much fraud there is, as I am not educated on the data.
However I would like to point out that your "staggering" data isn't necessarily staggering. Okay, 50% of racketeering cases investigated by the Labor Inspector General involved pensions and benefit plans. So what? The population if things the Labor Inspector General might investigate could be made up of 85% pension and benefit plans and 15% (insert other thing they inspect). Then the fact that 50% of cases were pension/benefit related isn't so "staggering".
And the fact that there were dozens of cases in 2020 is of course bad. But if there were 24 fraud cases out of 2,400,000 employers, for example, that just really isn't "staggering".
I don't point this out to attack you, nor am I trying to say pensions are awesome and always pay out. I just want to give some thoughtful feedback about how I think maybe your point isn't necessarily as clear cut as you think.
I don't know why I went to all this effort to make this point here, as it's not like this is your senior thesis. It's just a reddit comment and you're probably right.