Fritz didn't interrogate Oswald by himself, with no one else there. Hosty and Bookhout and others were in on the questioning too. So if Fritz lied about Oswald's statements about the curtain rod story, the bag, the backyard photos and other areas then these others went along with these falsehoods. And why would they lie about these things, about what Oswald said? What's the purpose? Just for the heck of it? Or to frame Oswald for the crimes? What's an innocent explanation?
So, we supposedly have multiple people lying about what Oswald said about critical issues in the assassination. But he's not saying there was a conspiracy to frame Oswald?
They all lied for what reason?
Their reports differ, no matter how you twist and turn it.
Yes, they claimed Oswald denied he carried a "long bag", but what exactly did they ask him? Did they ask simply if he was carrying a "large bag" (whatever that would have meant to him) or did they give a more detailed description in their question? We don't know, because it's not in their reports, which basically makes their reports worthless and unreliable.
They could have easily asked Oswald if he had carried a bag that was large enough to conceal a broken down rifle and when Oswald answered that he didn't, they just wrote down he denied carrying a large bag.
If, on the other hand, they had asked him if the bag he carried could have fitted between his armpit and the cup of his hand he might have said, "Yes, but that's not a large bag".
The quality of the question determines the quality of the answer and in this case we don't know what the question was they asked, which basically means they screwed up big time and all their reports are meaningless.