Lowry, 37, who won the 2019 British Open, announced the end of his sponsorship deal with Kingspan on Tuesday after the publication of the report into the blaze.
The 2017 disaster in west London killed 72 people and is Britain's worst residential fire since World War II.
Ireland's Lowry wore the Kingspan logo on the sleeve of his shirts while competing.
Asked Wednesday ahead of this week's Irish Open at Royal County Down Golf Club about his decision to end his partnership with Ireland-based Kingspan, Lowry initially declined to add any further comment to his brief statement on Tuesday.
Pressed on whether he could have made the decision sooner, the world number 32 said: "I can't imagine what those families have gone through the last few years.
"I'm not going to sit here and talk too much about it, it's obviously a touchy subject and my heart goes out to them."
Survivor groups have heavily criticised Kingspan, one of three firms that were singled out in last week's report.
The report exempted Kingspan, whose headquarters is in Cavan, northwest of Dublin, from responsibility for the spread of the fire.
But it found that the firm had "knowingly" created "a false market for insulation", had used "dishonest strategies" and had shown "a complete disregard for fire safety".
Survivors had previously accused Lowry of ignoring their appeals to ditch the sponsorship.
