RG:
You are incorrigible. Staying up on Shavuos night is NOT a halacha. It is a minhag. The sifrei halacha can set normative practice according to their judgment, and they concluded that this means just the first night. You cannot accuse them of guiding people to be meikil! That is a baseless shmear on these poskim, all of whom could outdo you in learning any day. You can strain yourself to remain awake the second night if you please, and it might just earn you some Heavenly points. Those points will be lost by judging other Yidden who comply with normative halacha/minhag as deficient or wimping.
One poster noted that Rav Elyashiv ZT”L did not stay up on Shavuos night at all. You would claim that he was mevatel a mitzvah, and that his doing so in order to function the rest of the Yomtov is hypocrisy. That chutzpah is unacceptable. Should you merit a visit to Eretz Yisroel, I would suggest you travel to Bnei Brak and visit his kever. You may ask mechila for suggesting that the Gadol Hador was a hypocrite.
Lastly, there is a concept called לפנים משורת הדין. It has many applications. There is not a single one in which the individual who does not do the extra is considered “less than” or meikil. You can undertake whatever chumros you wish. But following normative halacha cannot be blasphemed to be called meikil.
I will stop commenting on this, as you have made up your mind, and refuse to be confused by the truth.
I should add that the nazir is kadosh, as noted in the psukim referenced above. But he also brings karbanos of חטאת ואשם, as his choice of פרישות was extreme. That is what is derived from the seemingly conflicting divrei Chazal.