Permission to visit the Graves:
The Four main sects, shia's, deobandi's, brailvi's, and Whabbis have different point of views for visiting graves.
Shia's and Bralevi's encourage visiting graves. A good example would be Arbaeen, as mentioned in the question's link, where Million marches towards the Grave of Imam Hussain. They encourage this act through the following:
- Voice against oppression (as Imam Hussain stood against tyranny)
- Prayers alongside graves (as they ask for Allah's mercy for the sake of the person in the grave), also called In Reference to the person in the grave.
- Strong relation to Allah (as when they visit the grave, they remember that, this life has to pass on, and everything will be left behind).
Deobandi's and Wahabbi's discourage visiting graves. They support it by these points:
- One who is dead, cannot be asked from directly as it is kufr, Even from Prophet Muhammad (SAWW) as Zakir Naik(Deobandi) said on his address on television show.
- Some one cannot ask from anyone but Allah. As only Allah can help you.
The Main point of Argument Remain same always, Asking for Allah Mercy with-reference to the pious people who has passed away and Asking for Allah mercy without-reference?
With this Point in mind, do remember each sect follow its rules.