What is meant here by the imams losing their position, is the disregard for what their true position (that Allah (swt) had granted them and cannot ever be taken away) called for and what it was supposed to entail, and putting them aside in society, denying them their true social status. The reason being that the imams possess two types of positions; takwini and social. Examples for the takwini would be their being the reasons and intermediates of Allah's (swt) grace to all of creation and the main reason for Him showering His blessings on the people, them being the manifestations of the light of the Lord, them owning the keys to the treasuries of knowledge, the strongest way of connecting and getting nearer to Allah (swt), etc. Although all of these positions are endowed by Allah (swt) and man has no say in giving or taking them, the positions call for certain consequences that must be observed by the people; these consequences being the social status of the imams such as wilayah, government, and interpreting and explaining religious teachings and revelation for the people. These social statuses that the people must observe about the imams can be disregarded and taken away from them, as Imam Sajjad (as) says in a dua: “They usurped the rank of caliphate and imamate that through divine decree was under your command and management, they altered your decree, your book was deserted, the laws were changed and the tradition of the prophet (pbuh) put aside.”
Imam Baqir (as) says that on every eid the grief and sorrow of the Ahlul-Bayt is relived, because their right is in others’ hands. This is similar to what Imam Sadiq (as) has said about how Allah (swt) had given the Ahlul-Bayt the right of government and rule, but the Bani Umayyah (Umayyids) took it away from them.
To conclude, it must be said that although all positions, takwini and tashri’i, all are given by Allah (swt), but those who usurped the caliphate after the prophet (pbuh) and ignored his command, didn’t respect the position Allah (swt) had granted the Ahlul-Bayt, not to mention all the pain, suffering, torture, disrespect and murder they committed, both regarding the imams themselves, and their followers. All of this is in total contradiction with the true status of the imams, which is referred to in Ziyarat Ashura as putting them aside and depriving them of their position.
 The Arabic terms used in Ziyarat Ashura are دفع and إزالة, which have different meanings, but the most fitting meanings here are ‘to put aside’, ‘to deny’ and ‘to block and not allow’. The New Arabic-Farsi Dictionary, the roots of زال and دفع.
 Majlisi, Muhammad Baqir, Bihar, vol. 86, pg. 218.
 Saduq, Ilalul-Shara’i’, vol. 2, pg. 390.
 Kuleini, Kafi, vol. 8, pg. 266.