Indeed.
In BA the 777 is a longhaul fleet ( company definition) so LHR-TLV is a longhaul route.
OTOH if you use 6 hours as the cut then BOS-LHR on a 744 in winter (fast aircraft, strong tailwinds) could drop into shorthaul......
And as for JFK-LCY on an Airbus? Longhaul ( > 6 hours) or Shorthaul (shorthaul type)?
Definitely not an exact science.