Toxic is a loaded word but clearly their influence must have contributed to the malaise no matter what people think and that includes St. Harold here.
“Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.” - Sherlock Homes
They are associated with past failures, sure.
But what about the other fourteen/fifteen players who have only been in the squad for the past two or three years and achieved virtually nothing of note here in that time?
At least Kane, Son etc., can point to the glory days of reaching the finals and being involved in title races.