Re: When a pious person died they make a place of worship at his grave
No they are not open to massive wide interpretation. What you were talking about was life after death. The matter of help from the dead is different. Life after death does not carry massive interpretational differences. What you may see on forums is straight up Jahalat from people who are influenced by something else, like denial of possibility of help from passed away souls. They then take on other dark positions like denial of life in the grave. Not justifiable positions but dark jahalat.
Such positions are utterly ignorable, so there is no big interpretational differences among those who know the Quran and Sunnah.