Why are Gram-negative bacteria more resistant than Gram-positive bacteria to damage by certain chemical agents like lysozyme?

Gram-negative bacteria are more resistant to lysozyme and antibiotics than Gram-positive bacteria, because they have a largely thick impermeable cell wall (peptidoglycan), an outer lipid membrane that causes reaching of antibiotics to bacteria harder.

Gram positive bacteria have thin lipid peptidoglycan cell walls.