It is true that hindu society is more liberal than Abrahamic ones. But saying that "They do not constrain the followers to the teachings of predecessors" etc is not entirely true.
Also it is important to note that a community is the product of its time and location. So during a particular period hindu society may have been more liberal than during another period. Similarly during a particular period xtianity may have been more liberal than in another period. In a particular region moslems may be more liberal than elsewhere and so on.
Vedas, (Synthesis of vedas) Vedantas all are pointing to the same liberal concept and Hinduism based on these principles is always liberal through out history.
But Brahmanism started deity worship, that is the concept of personifying the GOD as Human, then Shivism and Vaishnavism fought each other, Idol worship also incorporated(nothing wrong if a common folk wants to communicate to GOD visualizing an Idol/picture of GOD in his mind), Since most of the common folk do not understand the concept in Vedas, Personifying GOD is a simple way of conveying the message of GOD to common illiterate folk at that time. Even in these times most of the people are liberal when it came to faith and worship.
Puranas(literature about favorite Diety), Shastras(Law of justice, rule etc...etc..) and Manushruti( a nonsense text about divisions of Hindu society which is an expired text) came later.
When Shankaracharya advocated the "Advaitha Philosophy" and started the revival of Hindusim he went back to Vedic period and declared that it is the Vedas that is basis for Hinduism. In Vedas every thing related to GOD and Dharma is liberal(as per my understanding).