I think the waters are being muddied by the timescales involved. Also the year of lockdown where people weren't around to notice a smell, if there were one.Just my opinion but I think questioning about the smell or lack of is a valid point of discussion. In other cases where individuals have been found dead 3+ years down the line, neighbours have usually noted a bad smell in the vicinity.
I think questioning the smell or lack of is fine, but throwing suspicion on any and all people who may have entered the house is a bit far.