How do we distinguish between BTC and BCH in an address? Bitcoin.com has recently published an article about the DOJ seizure of Silk Road-related funds. The article states:

From 1HQ3, 101 BTC were sent to BTC-e, the defunct Russian exchange.
About 69,370 BTC remained in 1HQ3 and were subsequently seized by the
government. The address also contains approximately 69,370 BCH, BTG,
and BSV prior to the government’s seizure.

What does this &quot;the address also contains&quot; really mean?
This sounds like the address contains 69,370 BTC + 69,370 BCH + 69,370 BTG + 69,370 BSV, and I don't think that is what they've meant. Do they only mean that the transactions are committed before BCH, BTG, and BSV forks happened?
How do we distinguish between BTC and BCH in an address?

By looking at the post-fork BTC and BCH blockchain transaction-journals independently.

What does this &quot;the address also contains&quot; really mean?

They are saying that in both the BTC and BCH blockchain transaction-journals there were unspent transaction outputs associated with an address that existed in both.

Do they only mean that the transactions are committed before BCH, BTG, and BSV forks happened?

That seems most likely.
Incidentally, since many addresses are created deterministically, I suspect it is possible that re-use of the same keys in both BTC and BCH wallets would cause either to generate the same sequence of addresses post-fork. I am not familiar with BCH and don't know if they continued to use the same HD algorithm, it seems possible.