Why? Because HCl dissociates completely into it's constituents ions while HOCl doesn't in the provided medium (H2O majorly).
Why this difference? The difference is in the strength of the bond between H and Cl and H and O. In HCl the H and Cl are surrounded by water molecules "pulling" the H-Cl bond apart with the electron pair going to the more electronegative chlorine atom, producing H+ and Cl-.
While in the case of HOCl, the H-O bond is stronger and shorter. This prevents the H from being hydrated to the extent that H in HCl is, and keeps HOCl from dissociating completely.
"Pakad ke rakhta hh, jaane nahi deta."
Also, The H in HOCl is very much like the H in HOH. We know that water does not dissociate very much, and so neither does HOCl.