How many times have we read that ALL Catholics are Christians??? I'll bet you've said it yourself...
"I know of many people who don't even claim to be Christian, who attend once or twice out of curiosity (and some of them convert); I know of others who are not validly baptized, but who still attend.Summary: "validly baptized" = Christian. Dismiss or argue that, if you like... but it soundly refutes the point which you're defending (i.e. that I ever claimed that someone is a Christian merely because of the "church" they attend). Someone can attend Catholic Masses as often as they like; if they're not validly baptized, they're not Catholic.