Despite the volatility in bonds, a fund like XBB is going to be less risky than an investment in Fortis, primarily because of the equity exposure you have in Fortis versus the fixed income exposure you have with XBB.
You're talking about a publicly traded utility versus an ETF comprised mostly of provincial and federal bonds.
That said, with the rapid rise/fall of interest rates, there is no denying that bonds have been more volatile than a utility like Fortis over the last bit. However, the heightened volatility doesn't necessarily mean there is heightened risk there, it just kind of seems like there is with a bond fund because of the fact that you are not given your initial capital back upon maturity of the bond like buying an individual one.
Bond funds have no real fixed maturity date, so people believe that the above concept of getting par value back at maturity doesn't exist with them. However, it still does, it just isn't necessarily as pronounced.