So, sure, use the texts. But you can't just point to a little passage, buried at the end, and say that all things are created equal. In fact, I am fairly certain that one of the core strengths of 4e is that it, in normal play, it constrains the DM more than other versions of D&D- that's why some people love it, and why some people consider it much easier to DM.
On the contrary. One of the core strengths of 4e is that
in actual play it supports the DM more and constrains them less. By constrains I mean forces them to wrestle with the rules rather than being supported by them. Here are some examples:
First, if you want constraining for the DM then go look at 3.X and the skill system for that game. For that matter if you want constraining
compare the 5e monster creation rules with its 20 step process that requires you to work out the CR to work out the proficiency bonuses of a monster and you need to know the attack bonus to work out the CR to the MM3 on a business card. And there is literally a blogpost that's high up the monster design searches called "
How to create a D&D monster for fifth edition in 15 minutes or less" For how constraining that looks to a 4e DM I've literally created three types of RAW monsters for a combat, each with different abilities, in the time it took to set the battlemap and roll initiative. And it was still a distinctive and successful combat.
Second one of the key things that differentiates 4e and makes it easier to DM is it works out of the box. 1e for example - how do initiative rules work? Yes, I know there's a textbook answer to that but then there are classes that make percentage change in it somewhere.
If in order to make something work at all I have to kitbash it then forcing me to do something is a constraint and a far bigger one than just not explicitly telling me I can do something.
Thirdly
if I need to look up anything in the course of play to run Rules as Written then that's a constraint that impacts me at the table. In 4e I
might want to look up the skill challenge DCs and the improvised damage charts
but this is never mandatory. In 1e I have to look up attack matrices and saving throw matrices as a matter of course. And then there's the details of how 3.X skills or 2e "Non Weapon Proficiencies" work.
Fourthly
if I need to lug books around with me and use them in play or cross-reference and cross-link things that's a huge constraint that impacts me at the table. When I run monsters in other editions
I need to look up their spells in other books. 4e frees me by meaning I don't need to do that. 3.X is the most constraining. 5e at least
largely (as it normally does) follows in 4e's footsteps and you only need to look up actual spells. Not as unconstraining as 4e but not bad.
Fifthly
even in a rules question having the rules on the character sheet is liberating while having to crack open books and search for the spells isn't. I've three or four times asked to see a character sheet and once said "we'll do it this way and look it up at the end" but don't recall
ever cracking a book in play over a rules dispute in 4e. In 5e I've needed to look up spells.
Sixthly
the most constraining thing of all is to be left utterly bereft of answers. 4e gives me tools to deal with daft PC plans (skill challenges) and improvised attacks in a way no other edition does. And yes, there is about an index card's worth of material I sometimes want to look up here.
Saying "Well you can hack it and throw things on here and there" isn't freeing until
after I've fought my way past the constraints the game decides to weigh me down to like a 20 step monster creation system that requires referencing itself. And yes I know Lanefan has fought his way past the constraining makework of needing to use a collection of lookup tables to see whether an attack hits and for saving throws - but I see no earthly reason that doing this would improve my game. It does however constrain me by giving me another thing to remember, to organise, and to run.