As discussed here: Definition and ritualistc rights of vrAtyas in the present day, it is clear that there are no pure Kshatriyas and Vaisyas today (there may have been at the start of Kali, but definitely not in the 21st century).
In the Kalki Purana, it is mentioned: "At the end of Kali-yuga, the Supreme Lord, Hari, will incarnate as Lord Kalki and kill all the mlecchas, yavanas, atheists, and Buddhists of the world that defy the Vedic authority"
My questions are:
How does Buddhism play into this? Why is the Lord so angry at Buddhists specifically if there are so many other mathAs that are Avaidika (ex: Jainism, Islam, Chrsitianity, tribal religions, etc)? Could these be interpolated prior to Adi SankarachArya when Buddhism was on the rise?
How do the current middle varnas (i.e., those passing themselves off as kshatriyas and vaisyAs, see link to question above) protect their lineage from the wrath of Kalki? It is said that He will exterminate those who are "un-Aryan", but as discussed in the previous answer above, everybody except for select bramhana families have had some sort of varna sAnkaryam and thus "mlecchatva", even if they do not want to admit it. If they (fallen dwijAs) continue to perform upanayanAs and pass themselves off as ksahtriyas and Vaishyas until that time, this means that they are unknowingly defying Vedic authority. Does that necessitate that their biological lineage will all be killed by Kalki? Or would Kalki try explaining that they are to follow the sUdra dharma instead?
How would Kalki re-etablish varnAshrama in satya-yuga if pretty much only a handful of sath brAmhana families would remain? There already are no pure seminal kshatriyas or vaisyAs.
Let us suppose after Kalki, certain Thenkalai Vaishnava AcharyAs and the Bhagavatham (https://indiafacts.org/understanding-the-concept-of-varna-as-it-appears-in-hindu-scriptures-ii/#:~:text=Bhagavata%20Purana%2C%20one%20of%20the,10) are accurate in their statements of the Hamsa Varna in the Satya Yuga. If the chAthurvarna is created every cycle from a Hamsa Varna which solely meditated "on the pranavA", then why would SwAyambhavu Manu reveal the Manu Smriti during his first Satya Yuga?
The Manu Smriti talks of places that are considered to be "Arya Varta": https://www.wisdomlib.org/hinduism/book/manusmriti-with-the-commentary-of-medhatithi/d/doc145592.html . It also speaks of "fallen dwijAs" such as the YavanAs, drAvidAs, etc. If SwAyambhu ManU is the first Manu, how were these tribes and places already in vogue? How are they already fallen? Are they re-created by Kalki after His re-establishment of dharmA or is it that Manu edits the sAstra prior to each chathuryugA?
Note: I mean no offense to anyone. This question is purely to understand the implications of sAstra in today's context and rituals; examples with references were provided to better frame the question.
May the Vedic Dharma and everyone in BhAratha flourish.