Question: is it a red flag if I'm "not supposed to" blog about tips and tricks I've found at work (not even code level, just organization and general design patterns)? Reason given to me: "we need to be careful about due diligence and intellectual property for our investors to be satisfied". Am I working with idiots?

maybe

Yes.
From A legal point of view, anything you "invent" is the IP of the company. So don't put Company, or new IP on your blog. Also - if your blog gets bad publicity, that affects your company.... Also very bad.
So:
Be boring, and Don't piss off people. And don't ask questions, just write a blog.

Also just wait to identify yourself till you leave the company
That ip crap is just that
You could be learning standard methods and yes you will take tips and tricks with you
Programming is pretty standardized really
And most people have a tendency to eventually reach the same conclusions. Via strategy because there are only so many things that work at the lowest and highest levels

Just blog under a pseudonym and never mention names. No one can then connect your blog to a specific company and then you are safe.

Honestly, using a real name online is still one of the dumbest thing people started to do

I mean only if you use the company's data or fail to deliver that the intelligence you write is common, they have a valid point. Otherwise it's clownry.

I think it's a bad sign.

Sure, they can do it, but why?

They are against collaboration, knowledge sharing?

Do they really think this is useful IP?

Who's running this show? engineers & managers or the investors?

Cuz investors are idiots. they just want to inflate the company value.

Intellectual property.

But yes.... Things like patents etc fall in the same category.

You can choose either money and profit or sharing of resources without claiming ownership.

@Hazarth Or under a coworker's name you don't like...

Let me clarify:
Using A timestamped blog can actually protect you from IP problems.
Publish anything you "invented" when you are between jobs. It becomes Public domain IP that way, and you can prove it exsited before you started work at new company, and old company can't prove you "inveted" it durimg your time there.