The word Sanatana is often poorly translated as "ancient." Its true Sanskrit definition is Nitya (नित्य - Timeless/Eternal) & Apaurusheya (अपौरुषेय - Not authored by any man).
Sanatana Dharma is not a religion founded in a specific century by a specific human prophet. It is simply the underlying operating system of reality. If a cataclysmic event happens tonight & wipes out every library, every computer & every memory on Earth:
Every man-made ideology, political party & dogmatic religion will vanish forever, because there is no living prophet to re-author them. However, within a few centuries, scientists & meditators will independently rediscover gravity, the laws of thermodynamics, the properties of sound frequencies & the architecture of the human mind.
That which will inevitably be rediscovered because it is woven into the fabric of nature is Sanatana. It is the default setting of the cosmos. Haters often attack religions because they find rules hypocritical/contradictory. Sanatana eliminates this entirely through the concept of Adhikara (अधिकार - Individual Qualification/Aptitude).
Sanatana does not force a uniform, mass-produced blueprint onto 8 billion unique human minds. It recognizes that humanity is an ecosystem of varying intellectual, emotional & psychological frequencies.
If we are highly intellectual & demand logic, Sanatana offers us Jnana Yoga (The path of pure philosophy & inquiry). If we are deeply emotional & experiential, it offers us Bhakti Yoga (The path of devotion). If we are a pragmatist who believes only in action & work, it gives us Karma Yoga.
It does not even mandate a belief in God. The Nasadiya Sukta in the Rigveda explicitly wonders if the Creator even knows how the universe began, openly embracing cosmic agnosticism. We cannot hate Sanatana because the moment we reject 1 aspect of it, it smiles & says, "That is fine, here is an alternative path designed exactly for your current psychological state." It is not a cage; it is a mirror.
The absolute core reason why critics melt when they understand Sanatana is that it structurally lacks the concept of The Infidel/The Heathen. In binary, man-made theological systems, the world is divided into Us vs. Them, Believers vs. Disbelievers, Saved vs. Damned. The ultimate goal is conversion/domination.
Sanatana operates on the non-dual baseline of Aham Brahmasmi (अहं ब्रह्मास्मि - I am the Cosmos) & Tat Tvam Asi (तत् त्वम् असि - You are also That).
When a critic stands up to attack a self-aware follower of Dharma, the Dharmic mindset does not view that critic as an evil sinner destined for hellfire. It views the critic as an expressions of the same unified, cosmic consciousness (Brahman), currently acting under the temporary evolutionary fog of Avidya (ignorance).
We can hate a book, we can hate a temple, we can hate a historical figure & we can hate a political decree. But we cannot hate a civilization that looks us in the eye & says:
"Your skepticism is valid. Your doubt is an expression of your intelligence. Search for the truth on your own terms, because whatever path you take to reach the ultimate reality, you are still moving within Me."