A few criticisms I found on the mailing list:

• It’s too complex / hard to understand for non lawyers
• The copyright notice requirements are annoying
• The patent provisions make the license non free
• It’s worse than the previous license.

From: Henning Brauer (lists-openbsdbsws.de)
Date: Thu Feb 19 2004 – 02:58:21 CST

the point is that more and more free software is slowly getting unfree,
more restrictive, etc, and that is not something we should just
passively watch.
please have a look at the new apache license.
it is not really parsable without consulting a lawyer, and as this
license seems to go into the contract law land, the lawyers answer
migth very well be a differing depending on in which country you are.

From: Steve (steveszmidt.org)
Date: Mon Jun 07 2004 – 13:59:03 CDT

Yes indeed. Reading the Apache 2.0 license, it demands notices to be placed in
any modified versions that you distribute. BAAD!

It even have the gall to demand that if you “prepare Derivative Works”, “to
carry prominent notices stating that You changed the files”. Including
original copyright notices and stuff.

This is truly evil.

Besides being so nasty it’s a really easy to read license for any layman.
Guess they figured that if anyone can read and understand it they will stay
away from Apache.

To cap it off, unless you explicitly state otherwise, any contribution
intentionally submitted, will follow the same license! So now others in
their turn also have to include notices and so on. This is a truly unfriendly
license…

From: Theo de Raadt (deraadtcvs.openbsd.org)
Date: Fri Feb 20 2004

No sorry, the Patent clause seems to give extra rights: the right not
to be sued by a contributor for using their code, so in that sense
the extra length does seem to make the licence more free.

That’s funny; I cannot see any such thing being covered by copyright
law. As you may know, copyright law only allows you to keep or grant
away the rights covered by copyright law. And since this is a right
not discussed in copyright law, good god, it must not be a valid
copyright term.

There has been a load of knee-jerk nonsense from people who clearly
can’t (or don’t want to) read, asserting that this removes users
rights to sue. It doesn’t, it merely removes rights if they sue that
they would never have had under a BSD licence in the first place.

Balony.

What bothers me is a bunch of OpenBSD folks going over to Apache
licensing lists making assertions that clauses like the patent clause
make the license inherently less free based on poor analysis.

It is not free. There is no such thing as a “right to not be sued”.