Indeed. They were planning to rip out and replace the pad anyway, and believed that they’d at least get one launch out of the existing one, so they saw no reason to delay. If they’d waited for the new pad to be installed they would only just be gearing up for their first test flight right now. They’ve had four months to refine the rocket’s design based on the data they got from the first test launch.

They misjudged the robustness of the original launch pad, but only somewhat. IMO the much more serious misjudgement was their flight termination system, they blew holes in the ship’s tanks when it started tumbling out of control and it took something like 40 seconds for the ship to finally disintegrate after that. That was a situation where they underestimated the robustness of their systems. The new flight termination system is much more powerful.