I can tell you with certainty this is not true with the majority of lenders. I can't answer for Gander Mountain as I never applied for that card. I have all three scores over 800, pay my cards off monthly and admittedly I have - we will just say a large amount of available credit. Lots of credit cards. Lots. I never pay interest. Lenders make plenty of profit off of me because of fixed transaction fees, and percentage of sale. The difference is that I am a heavy credit card user. They do not earn interest off of me, but they do earn fees. That is enough for them. I have never been denied any card I have wanted. I never apply for store only cards. They are all Visa/MC/AMEX/Disc which can be used anywhere is in the US.Do a Google search. 800 IS indeed the point where they consider you to have credit that is too good.
Gander Mountain sued their bank because they were turning down anyone who had a score of 800 and above. The bank said it was hard to make a profit off of those customers. Banks like people to make payments or even make late payments due to the increased fees involved.