that is because of the laziness of the website designer that only copied things from the alternative block explorer for BCH so now it says on top BSV explorer and the blocks are for BSV but he has forgotten to rename the term "BCH" to "BSV".
It seems like everything pertaining to BSV was thrown together in quite a hurry. I don't think CSW ever envisioned a scenario where his client did not win the battle for the BCH symbol. Websites, wallets, partners and block explorers were all developed after it came to light that there would be two coins as the result of this mess.
all of it has been a terrible mess! it is a full on war and the fires of it has been burning the whole market not just these two altcoins. having silly things such as wrong abbreviations are too small in comparison!