Why do you feel a need to say this, bro?
The people who don't have a 3 hour Nitnem are not "Punjabi Hindus". I don't know what circles you inhabit, but there are vast numbers of people who aren't in complete Rehit, but are not Hindus by any stretch of the imagination. They do not worship idols, they don't go to mandirs, and when they encounter difficulties or happiness in life (like the birth of a child), they go the the Gurdwara. They may not recite Sukhmani Sahib every day, but they definitely don't recite Gayatri Mantar, either.
As far as the definition of a Sikh as per Gurbani, there may only be a handful of people in the entire world that meet that definition. I.e., people who recite the Naam with every single breath:
ਗੁਰ ਸਤਿਗੁਰ ਕਾ ਜੋ ਸਿਖੁ ਅਖਾਏ ਸੁ ਭਲਕੇ ਉਠਿ ਹਰਿ ਨਾਮੁ ਧਿਆਵੈ ॥
Gur Sathigur Kaa Jo Sikh Akhaaeae S Bhalakae Outh Har Naam Dhhiaavai ||
One who calls himself a Sikh of the Guru the True Guru shall rise in the early morning hours and meditate on the Lord's Name.
ਗਉੜੀ ਵਾਰ¹ (ਮਃ ੪) (੧੧) ਸ. (੪) ੨:੧ - ਗੁਰੂ ਗ੍ਰੰਥ ਸਾਹਿਬ : ਅੰਗ ੩੦੫ ਪੰ. ੧੬
Raag Gauri Guru Ram Das
ਜੋ ਸਾਸਿ ਗਿਰਾਸਿ ਧਿਆਏ ਮੇਰਾ ਹਰਿ ਹਰਿ ਸੋ ਗੁਰਸਿਖੁ ਗੁਰੂ ਮਨਿ ਭਾਵੈ ॥
Jo Saas Giraas Dhhiaaeae Maeraa Har Har So Gurasikh Guroo Man Bhaavai ||
One who meditates on my Lord, Har, Har, with every breath and every morsel of food - that GurSikh becomes pleasing to the Guru's Mind.
ਗਉੜੀ ਵਾਰ¹ (ਮਃ ੪) (੧੧) ਸ. (੪) ੨:੫ - ਗੁਰੂ ਗ੍ਰੰਥ ਸਾਹਿਬ : ਅੰਗ ੩੦੫ ਪੰ. ੧੯
Raag Gauri Guru Ram Das
So if you missed a breath, you're not a Sikh.