Because each deity is something or the other of the Divine Mother one can no doubt, through strong faith and intense aspiration approach Her through any form or name. But this is a long indirect route and it is quite likely that the bond forged with one deity may itself become a bondage to going further. This is not only because the human mind gets attached to a particular form and name but also because the deity develops an interchange with the devotee and hence doesn’t let go of him. That is the story of Sri Ramakrishna and Kali Ma when Totapuri wanted him to go further. Besides each form and name has a certain purpose, a particular force and function. That is why it has come into being. It is not easy to go past it for something greater and beyond. It has always been known that the gods too can come in the way of our progress if we try to go beyond and form a direct relation with the Supreme.
Affectionately,
Alok Da
Follow up question:
Please also explain what tantra makes evident about the divine mother-Shakti?
Tantra in general is about the Shakti, the Power of the Divine Mother in different aspects. The Shakta Tantra, the Dashmahavidyas, the Devi Mahatmya are all about the Divine Mother. According to Tantra, it is the Divine Mother who is the Origin of all things including the Deva himself who is void of power without Her. She is the devatmashakti, the power of the gods.
Affectionately,
Alok Da