I'll take the opposite approach : why should necroing be forbidden ?

In the name of what should someone interested in a topic be forbidden to participate in it just because it is old ? (or create another one)
This is totally silly.

Let's push it to the limit :
Someone has a technical problem with a game that no one found a solution to. Years after someone else stumbling upon the thread has the solution. So just because the thread is old he shouldn't have the right to post the solution ? Silly as fuck.

It's as if people are eager to find justifications to enforce their power and feel powerful.
Pitiful society...

Because zombies shambling all around are very unhygenic. And skeletons make way too much noise.

yep i would just remove that rule, and probably a few other rules which make no sense
but as long as it is there, they should implement an automatic solution over this manual time-consuming one

But... necromancer is a cool class to play !

In my experience only a fraction of threads were locked after a sudden *necro resurrection*, most of the time those threads were related to some sensitive cases with GOG to which mods were swift to act in accordance with the rules. Maybe just a coincidence of course.
Some threads which were *necroed* after 2 or even 6 years by trolls, bots or with the help of special people were ignored completely. I'm certain no one was really interested to check on them.

And I must agree that if a new significant information is ready there is nothing bad in *necroing* the most recent but yet an old thread and to enrich it with a new game solution, fix, mod, pack, etc.
But what is an old thread? More than 2 years? More than 6 months maybe?

To clarify things a bit. We don't close every necroed thread. If the person who does this shares a valuable opinion or asks a valuable question, we leave the topic open. It's also important whether the OP information are not outdated. If there's a possibility that they might confuse some users, we decide to close the thread. It all depends on the particular situation.

Legalize necromancy!

No, absolutely it should not do that.

Doing that would result in the official main thread of all the games that have come on GOG being locked, the same main threads that are linked-to on the store pages.

There always might be legitimate reasons for users to post new comments in those old threads, yet if GOG did what the OP is suggesting, then they wouldn't be able to. Agreed, it shouldn't be.

Oftentimes threads are necro'ed by way of someone posting a spam comment into that thread for no reason.

But that's a spam problem, not a "necro" problem, and the concept of "necro'ing" shouldn't be looked at as a bad and forbidden thing on the basis that it's being illegitimately conflated & muddled together with the concept of spam.

Returning old threads should be encouraged. Anti "thread necro" is a bad idea. Old topics should not be locked. If moderators go around closing "necros", they're doing things wrong. Target the actions of off-topic posting and shitposting, rather than returning old threads with new information, updated information, or reviving a topic that's still worthy of discussion.

I've been seeing necroed threads being locked even if the user who reopened them wasn't spamming. And even if they are being reopened by spam, then just the spam should be removed, without taking away the option of someone else posting something relevant there in the future.
Now if the rest of the thread is no longer relevant, yes, that makes some sense, but otherwise this policy is just wrong and leads to the loss of potentially valuable information.

This was closed for "necroing": https://www.gog.com/forum/general/the_covid19_thread_redux/page21

Exactly ! Spam is the problem, not the necro.

Necro posting should only be against the rules when you're bringing up an old post to add nothing to it (like a certain person named orkhepaj has done recently). If you're adding to the discussion or asking a pertinent related question, why would a necro post be bad?

This forum is extrmely prejudiced against Orkhepaj.