Word ‘Hukam’ has multiple meanings and there are different types of Hukam in Gurbani. What you are asking about is what a lot of people get confused over. Because on one hand, Gurbani says everything is in Hukam and then on the other instructs us to follow the Hukam, The fact is that Guru Sahib is referring to two different types of Hukam.
First Hukam is Creative Will of God i.e.
ਹੁਕਮੈ ਅੰਦਰਿ ਸਭੁ ਕੋ ਬਾਹਰਿ ਹੁਕਮ ਨ ਕੋਇ ॥
ਹੁਕਮੀ ਹੋਵਨਿ ਆਕਾਰ ਹੁਕਮੁ ਨ ਕਹਿਆ ਜਾਈ ॥
This Hukam refers to God’s Laws according to which the entire creation operates. No one can change these laws and no one can escape them. For example, law of karma (you reap what you sow) applies to all and everyone is judged based on their earned karma. There is no way for anyone to escape karma. Another example is salvation which is only possible through Naam obtained from Satguru. There is no other way. No one can either change it or escape it. The entire creation is under the rules created by God. This is the Creative Will. This is united with God and has no end to it.
Second is Prescriptive Will i.e.
ਹੁਕਮਿ ਮੰਨਿਐ ਹੋਵੈ ਪਰਵਾਣੁ ਤਾ ਖਸਮੈ ਕਾ ਮਹਲੁ ਪਾਇਸੀ ॥
ਤਨੁ ਮਨੁ ਧਨੁ ਸਭੁ ਸਉਪਿ ਗੁਰ ਕਉ ਹੁਕਮਿ ਮੰਨਿਐ ਪਾਈਐ ॥
This Hukam refers to what has been prescribed to us i.e. rehat. Amrit Vela, Dasvandh, Seva, Simran etc. are part of Prescriptive Will so we know how to live our lives. No one is forced to accept this Will or follow it which is why Guru Sahib instructs us to obey it because we have a choice. If we follow it and get blessed with Grace of Vaheguru then we get salvation. If we don’t follow it then we get judged based on our karma (part of Creative Will).
Both are separate and unique yet work together. This is where it gets a little complicated. Let’s take karma for example. All karams have already been created by Vaheguru and the results have also been created. This is Creative Will which no one can escape. We simply pick and choose karma to earn. If one did not follow the Prescriptive Will then he made a bad choice and went astray. Thus, he made mistakes. Making bad choices results in distancing oneself from God, hence, that person is Bhulla. The result is based on Creative Will. No one can do bad deeds and expect a good outcome because Creative Will does not allow it. So it is due to Creative Will that the person becomes Bhulla. In other words, people who do good and bad deeds make choices only to determine which karma to earn but they cannot create or make their own karma. This is why Gurbani posits the question (instructing us to reflect upon it) whether a person became bhulla (through his own karma) or it was God whose Creative Will has already set such rules in place. The gist of such verses is that since we cannot escape Creative Will, we must always remain humble, gracious, and thankful to God rather than asserting ourselves to claim credit for karma. Otherwise we will fall prey to haumai. Gurbani is telling us to rely on Grace of Vaheguru and whenever we do good deeds we should be thanking Vaheguru for He is independent of all rules, above and beyond karma and the only liberator. Guru Rakha
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥