Carbon Copying Emails; a Questionable Practice

I just received another email from a government affiliated agency. Although probably still legal, I do have concerns when I see my email address and hundreds of our competitors' emails listed in any correspondence (especially confidential matters). The practice known as carbon copying embeds actual email addresses in the message. Some would argue this is not such a big deal but privacy advocates have a very different view. 

In theory, BCC (blind carbon copy) would avoid this problem but somehow the issue does not seem to concern many senders. A message could also be sent individually to each recipient using an email client custom tailored for this purpose. Both options would appear more secure and it is troubling to think that this practice is allowed. If a malicious third party decided to use this to attack key contacts at major companies, the result could be catastrophic. Moreover, competitors could even siphon off talent by farming lists of contacts with specialized skills. The field of computer electronics is an evolving science. We certainly do not know all the ramifications of bad practices but clearly if it seems questionable, why would anybody do it?