Then do you people conclude that the Vedas that promote tattva teach only vaisnava-dharma and no other religion?
Dharma is one, not two, and it is also known as nitya-dharma or vaisnava-dharma.
All other forms of naimittika-adharma taught in the Vedas are simply steps leading to that eternal religion. Sri Bhagavan has said:
Srimad-Bhagavatam (11.14.3)
“The Vedas contain instructions on bhagavata-dharma. At the time of annihilation, that message was lost by the influence of time. Then, at the beginning of the next creation known as Brahma-kalpa, I again spoke the same Vedic message to Brahmaji.”
The Katha Upanisad (1.3.9) states:
“I shall now describe to you in brief that ultimate truth that all the Vedas have repeatedly described as the supreme object of attainment. That abode of Visnu (the all-pervading Paramatma, Vasudeva) is the only Supreme Destination.”