OP, I share in your concern and sentiments. If people get tagged for scam activities and posts are deleted for seemingly being off topic or substandard responses, I don't see why the major issue of companies accused of scam activities shouldn't be controlled too. It's like catching the small thief and letting the bigger thief go scotfree.
Nothing related to scams or scam attempts is being "controlled" or moderated here. I don't like that policy, but that's the way it is. If the post or thread you made breaks other forum rules, that will be the reason it gets deleted. But not for scamming. You could literally start a "if you send me 1 Bitcoin I will send you 2 Bitcoin back" type of scam and if admins follow their own rules, they can't delete or trash that. If they do it to one thread , they'll have to do it to all the others as well.
Also, when someone gets tagged, he gets tagged by a member of Bitcointalk for reason X. That member doesn't speak for the forum and it's owners and operators. The tag doesn't show Bitcointalk's opinion about a user.
Also this is Bitcoin forum, the forum remain decentralized like Bitcoin. Moderating scam will make it less decentralized.
Bitcointalk is not decentralized. It's an online forum to discuss Bitcoin that has its rules, admins and moderators (a centralized group) that make sure those rules are being respected. If you get banned, you will get banned by a centralized group of individuals. If you appeal your ban, the same centralized group decides if you will be given a second chance.