No, bond ladders are not strictly better than a bond fund. In theory, they are equivalent. In a bond fund, you simply see your loss on rising interest rates more directly.
Scenario 1 (holding bonds to maturity, i.e. bond ladder):
Let's imagine you invest in a $100 1yr bond at a 2% rate. You will be paid $102 in a year's time. Immediately after you buy the bond, the rate goes to 3%. You are locked into the bond, so you can't switch to the higher rate (i.e. you've lost out on a potential $1).
Scenario 2 (bond funds, ignoring reinvestment):
Instead imagine that you invest $100 in a fund that currently holds 1yr bonds at a 2% rate. You expect to be able to sell this fund in a year's time for $102. Now the rate changes to 3%. You are not locked into the fund, but the fund is locked into the bonds that they bought. If you can sell your shares in the fund for $100, you could then buy the new 3% rate bonds directly (i.e. you have avoided the loss due to the interest rate change). This would be a risk-free arbitrage between the fund and the new bonds. The price of the fund needs to drop to ~$99 to be "fair" (to be precise, it's 1.02/1.03, not exactly 99). If you sell at ~$99 and buy new 3% bonds directly, you will receive $102 in a year's time, just like scenario 1.
In short, the bond fund loses value because you maintain the optionality to withdraw whenever you want (and invest at higher rates if rates go up). The expected value between bond funds and bond ladders is still the same. In essence, the difference is between holding bonds to maturity and having the possibility of selling them, which doesn't change the expected value.