What do you guys think about this argument against the riots?

As I understand the argument, there are so many issues, it's hard to pick out just one.

1.  The riots are causing many buildings to be destroyed.

Is it true?  If it's true, are there any occasions in which buildings' destruction is acceptable?  Are any of the acceptable occasions relevant to rioting? Can people destroy buildings without consequences?  Does the answer depend on any legal matters (ownership, permitting eg).

2. Destruction is bad. (implied)

Relating to part of 1, is all destruction bad?  If there are exceptions, are any consistent with the process of rioting?

3. Therefore the riots are bad.

If, after review of 1 and 2, the facts of destruction are known, the legal issues of buildings' ownership and permitting do not support the process, and the exceptions in 2 are not consistent with the process of rioting, I'd say the conclusion is inescapable.

Premise 2 isn't necessarily true, so this isn't valid.

These life-saving antibiotics cause diarrhea.
Diarrhea is bad.
Therefore, life-saving antibiotics are bad.

Form:

A (diarrhea) is part of group B (life-saving antibiotics).
A has the property X (bad).
Therefore, B has the property X.

This is a classic Fallacy of Composition .

A note about this fallacy: the form is fallacious, not necessarily the conclusion.

Murder causes suffering.
Suffering is bad.
Therefore, murder is bad.

Technically, fallacious in form no matter how right it sounds. Murder is bad (most would agree) because of the overall reduction to well-being. We can think of times we suffer for the greater good (like surgery). This can get us into deep philosophical discussion about moral reasoning, but for the sake of that discussion, let's say the foundation is well-being.