The fact that you started your 'question' with a 'so' suggests you don't actually care about my answer, you seem to want to justify bad behavior you disagree with, while pointing to other bad behavior (which isn't actually equivalent).
No.
that prevents software authors from making changes to said code that may behave in ways users do not like, or which may break functionality?
Laws don't work that way. Laws don't 'prevent' anything, they can however disincentivize certain behaviors.
Even if there was some sort of law which applied to this, there is a bit of a difference between feature changes with *may* break functionality and malicious changes. Kind like the difference between regular apples and applies sprinkled with laxatives... the very example I used above.
What about functionality that Microsoft / Apple removes in one of their many updates?
Still not equivalent. There is a difference between Microsoft / Apple deciding that a certain feature isn't widely used and no longer worth the costs to maintain/support and rage quitting and taking their ball home because they didn't get their way from people who are complying with the license but who aren't giving even more $ to.
More over, most vendors like that are pretty up front as to which features are going to be removed, as a warning to those who may want to keep it and so should take steps to avoid updates.
Many of these are not in the users interests,
Says who? How many users? Again... depends on the why.
but the nearly-universal narrative is that they have every right to do it, and if you donâ(TM)t like it, use something else.
Yup, and it's still not equivalent.
What about when a phone manufacturer bricks you phone for rooting it?
Was that 'feature' discoverable prior to purchase? Even being able to ask that question again, demonstrates you are not choosing equivalent.
Besides, I am unaware of any companies which deliberately brick phones after they are rooted. Depending on the situation, it may actually be called for.
We tend to be outraged when a powerless plebe adopts the tactics of the rich and powerful. Much more so than we are with the rich and powerful themselves.
Except as demonstrated here, the 'powerless pleb' looks to have had far more power than you will admit. What that 'pleb' did was out of spite and malice, and not for any other reason which those 'rich and powerful' can more legitimately point to.