In general I dislike advertising industry, just like I dislike the banking industry, or the gambling industry, but I think the comparison to a crime syndicate is not a good one. The difference is that the existence of both is within the boundaries that are specified by law, which is the most objective mechanism that we have to define something as honest. I don't think the law is always right, but it's got to count for a bit more than each individual's subjective morals. Because in principle it tries to break down things and isolate exactly what is problematic, which is something we're not doing when we pass general judgement in the form of an opinion.

Wouldn't you agree for example that collecting and analysing user data for purposes of displaying relevant advertisements doesn't have to be dishonest, if the users consented to it? Maybe then the problem becomes that some methods of obtaining user consent are not honest -which would mean that there could be methods that are honest, and companies that can follow them.

And if the subject is so nuanced then maybe it's not fair to say that an employee that simply wants to work in their domain of expertise doesn't do honest work, just for failing to set more strict standards than the law with regards to their employer's activities.