> Because they placed the content on a public website.

I don't think this is a very good argument. For instance, if I have a company, called 'tickle-cats', I may expect regular customers to go and tickle a cat for, say, 1 cent, as cost. So I would expect regular people to visit my homepage.

I may not necessarily expect or want to have bots, scrapers and what not, per se. I may have this by extension - possibly, e. g. to rank a website more highly. But bots and so forth are not my real target audience to begin with (and some are just malicious, trying to disrupt the business); some company owners may want to not have to do anything with them (bots, crawlers etc...). That's just one example of many more; I don't think the distinction "public versus private" is the only one that can be applied here.