I am a lefty, and after taking my required Marketing and Stratigic Mgt. courses I understand why they got to do what they GOT TO DO.
They too have to make a profit, and in the manufacturing biz time is money. Re-tooling takes time, using those machines increases wear and the occasional blemish that gets a piece trashed, and in general us leftys dont really account for 10% of the market that we think we do.
If they drilled the holes they MIGHT see a increase in sales by a small fraction. The real money to be made in the knife industry is in the $40-$60 range, and all of those do have ambi-clips. The +$100 portion of us knife buyers is significantly smaller, and although makers listen to us, I dont think it is because they absolutely need to (look at CRKT, a good knife for $30, but not a Spidie). I think they listen to us for new ideas, "Oh Yeah, I shoulda done that!" type of improvements, and generally to be artisticly challenged.
As strictly a lefty, yes it angers me, but from a business perspective I understand. Better to have a right hand Spidie than no Spidies at all.