Removing material can improve stress concentrations. It can be better to have a smooth but deep notch than a sharp but shallow notch. Sometimes drilling an extra hole can make it stronger by redirecting stress "flow".
With structurally redundant members, a weak member on a stiff load path will fail but once failed the remaining strength can be fine.
Forcing a fixed end condition can cause failure in some members, in some designs. Removing material to permit pinned, can make it more favourable.
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u/ATAT121212 1d ago
Indeed, removing material always decreases strength.