I think you raise some good points, but I still see value in surveillance testing.
Yes, depending on the frequency of the testing, some cases will slip through, but many (Perhaps most? Depends on frequency) will be caught in time to alert the infected individual to isolate and/or be VERY careful with quality-masking and distancing so as to prevent a large amount of transmission. Testing is not perfect, unless perhaps it is performed daily—but that does not mean it isn’t one of our useful tools. Masks are also not perfect, but they too prevent a good amount of transmission. Vaccines also are not perfect, but they are another (probably the best) tool to prevent a good amount of transmission and minimize harm/sickness. Combining these tools increases the effectiveness.
I am very upset to keep hearing about young people with breakthrough cases where they feel absolutely lousy—very sick akin to the flu or worse. This is not alarming in terms of danger, but I don’t know anyone who wants to go to class if they are comparably sick to having the flu. (Not all the breakthrough cases I’ve heard are this bad—I know of one asymptomatic, 3 that I would consider truly mild like a cold, and 2 that are in this category of really lousy). When medical people refer to cases as “mild”—I think they mean clinically mild—i.e., not hospital-worthy. To me, mild would be milder than that! I like to think mild means you don’t really feel bad, but I think these medical reports citing mild cases can include ones that are full-blown-flu-level-or-worse-yet-not-requiring-the-hospital-and-can-manage-at-home-types of cases. Meaning mild can = miserable.
So I’d still hope many campuses can try to reduce transmission to minimize disruption to all the awesome things campuses should be providing (in-person classes, in-person dining, in-person ECs and lab experiences, spectator sports and performances, social gatherings and parties, etc).
It’s a bummer to see that MIT is still experiencing transmission despite all of their precautions, but I have to think all of their tactics are helping to significantly reduce transmission and the number of people who feel lousy (and possibly pass it on to someone who may react worse).
I think the surveillance testing can also be useful to the schools as a learning mechanism—helps them know what is going on with spread to better inform all of their decision making. Perhaps the testing will reveal that after a few weeks there are no more cases on campus and a real bubble has been formed—then they might decide to drop masks. Perhaps the testing will highlight rampant spread and other decisions might be made. But I can’t imagine not wanting to know. Similarly, as an individual, I would like to know if I was positive. Why wouldn’t I want to know so that for a few key days I can try to protect others? I’d hate to think I was unwittingly walking around giving covid to others (EVEN if it only results in bad colds/flus for some of the people). I would think our kids similarly would not want to unwittingly infect others.
But I’m in total agreement in terms of hoping, praying, and counting on a really great (and largely normal) semester for these kids! 

