It's not always true that a vendor receiving money will increase prices to pass the PayPal fees to the consumer. You can see that many checkouts offer multiple options (e.g. both PayPal, Stripe, and/or other methods), with the item price usually the same even if each method has a different fee. The idea is that you want to make purchasing as convenient as possible, as it costs more to lose a sale, versus paying an incremental fee difference with PayPal.

If a vendor makes PayPal purchases slightly more expensive, it can cause bad will with the customer (who is less likely to return and make more purchases). Exceptions are sometimes with one-off purchases (e.g. a conference ticket or course fee).

Separately, the original comment asserted that the PayPal account charges you each transaction (which is false). The new argument is different, which asserts that a vendor may charge you more due to PayPal fees.