Well, scaling used in what context? If you're a "fader" (so sorry, let me re-phrase to the term 'mean reversion' trader) or a market timer (you're right and everybody else is wrong) then of course scaling might aptly be labeled a "crutch for the weak".
If you're moving size then you are usually scaling. Depends on what you're trying to do and how liquid the market is. For me, I have to take arbitrage into consideration as a spread trader. If I take a market sellers, for example, with one order I might not get my other leg executed in an ancillary and correlated market at the level I need. So instead of selling 300 I might sell as many 50 lots as I can provided the price levels are where I need to be.
For me, alot of it depends upon if the exchange order matching algorithm is FIFO or Pro-Rata. I scale all of the time and virtually every trade I take - both getting in to and out of the market. But it's not because I'm the cat's ass, it is out of pure practical necessity.
When you start trading size, you will find that you pass on some trades and in general you go about things a bit differently. I quit trading Liffe Euribor because they capped the FIFO at 200 before Pro-Rata kicks in. Took it elsewhere. Leave all the gamesmanship to the spoofers. I'm not going to bid 1,000 to get 50 like the 'flippers' of the world.