You are right, I think, to point out that Wesley's "Catholic Spirit" sermon is misunderstood  and misrepresented   when it is used tosuggest that Weley was not concerned with "right doctrine"


On the contrary , in that semon he is explicit that he is not suggesting indifference in matters of belief and worship.
""A man of a truly catholic spirit... is fixed as the sun in his judgement concerning the main branches of Christian doctrine. It is true, he is always ready to hear and weigh whatsoever can be offered against his principles; but as this does not show any wavering in his own mind, so neither does it occasion any. He does not halt between two opinions, nor vainly endeavour to blend them into one. ".....

But he does also argue that, as human beings, none of us is capable of perfect  (infallible) understanding. "...although every man necessarily believes that every particular opinion which he holds is true (for to believe any opinion is not true, is the same thing as not to hold it); yet can no man be assured that all his own opinions, taken together, are true.  ...Every wise man, therefore, will allow others the same liberty of thinking which he desires they should allow him; and will no more insist on their embracing his opinions, than he would have them to insist on his embracing theirs. He bears with those who differ from him, and only asks him with whom he desires to unite in love that single question, "Is thy heart right, as my heart is with thy heart?" "


The "Catholic Spirit" semon is linked below, and I think best read in its entirety for most complete understanding.

http://www.raptureme.com/resource/wesley/serm-039.html