I do it constantly, best way to average into bottoms to get the most of out a swing. Adding to breakouts is a standard consideration, nothing wrong with adding to winners. Naysayers simply don't have the buying power to handle temporary losses and/or refuse to look into options to offset the temp loss or lock in alpha. Naysayers may also be in the habit of buying subpar stocks.
Oh, I’m sure you can blow out in no time adding to a stinker spread position as well. From what I’ve seen over the years - most traders that blow out do so from adding to losing positions. Conversely, I’ve seen traders make fortunes pressing winners. The key operative phrase being “winner”.
Well, I guess spreading is less sicker than just going all delta on one leg. That's what I was getting at, as I assumed that was what the OP was on about. Just adding into a losing single leg.