How to prevent LinkedIn from showing the name to others in their feed as a group/brand’s without having to unfollow it

You can click the "See More" link at the bottom of the Jobs pane which opens up a new page with an expanded list. On that page you can use the faceted filter boxes at the left to narrow the listings. Unfortunately, however, there is no way to permanently save your preferences in this regard.

Note that the "Jobs you may be interested in" feature is still in Beta, and they are actively soliciting feedback (see the link at the bottom of the page), so I recommend clicking that link and making this suggestion.

LinkedIn is an unstoppable and unwinnable spammer, there is no way to really unsubscribe. To avoid receiving their emails, I registered and disabled all emails in the settings. Once you've done that, you can forget LinkedIn forever.

When you can't beat them, join them.

Otherwise, if you want to choose a longer route and if you are in a lucky country with privacy protection, you can of course complain to the relevant authority: http://ec.europa.eu/justice/data-protection/bodies/authorities/index_en.htm