What??? The existence of a law against any specific or general act is necessary for taking legal action. Your unnecessarily crude example is a violation of an existing law. Box checked. It's not a violation of the Sherman Act (Clayton Act, FTC Act), so let's stop talking about that example, thanks.

The question in the air in these cases is whether Deere, Apple, etc. are violations of specific anti-trust laws -- the language of those law is intentionally open-ended, and there isn't a ton of case-law. Thus, these cases have a high chance of setting precedent.

Now, it seems that what you're suggesting is that we should be able to punish companies, people, etc for being "bad" just because we know it's "bad." This sort of "justice" is literally arbitrary, and leads to incredible injustices. The closest remedies we have as a people, if this behavior is found to not violate existing anti-trust laws, is to persuade Congress to pass new laws (good luck), pass a constitutional amendment (nope), or to wage a class-action suit (here's your gift certificate for a can of beans).