The same Giroud who is 7th highest scorer despite being plainly out of form Giroud? He's a good player, get off his back.
In Welbeck's higher scoring season, how many did he get? Does that make him a good player?
Goal scoring doesn't make a player good, the vast vast majority of his goals have been <6 yrd tap in's, you or me would score most of the goals he has. A good player can create his own chances, provide a threat from anywhere on the field, etc. Giroud is not a good player. He tried basically once(thankfully) in the first half to pick up the ball from outside the area and run at goal, he looked hopeless, his attempt to take the ball around the defender was clumsy at best, he gave it away and it was easily dealt with. That is Giroud, effectively zero threat more than 10yrds from goal. Also scored quite a few penalties.
Simple fact is a striker of ANY quality will score more for Arsenal with Wilshere, Ozil, Ramsey, etc, behind them than they would at Palace, or Hull or, any other team.
What is a better(but by no means complete) comparison is chances taken, type of goals scored, ability outside of goal scoring. He has one of the worst conversion rates in the league, his ability at running with the ball is embarrassing for a player at a top 4 club, he makes Walcott look world class by comparison.
He very rarely scores anything but tap ins, is poor outside the box, is hopeless on the break. He was involved in really one counter attack, despite space to run into his second touch was passing it out wide to someone not in an ideal position. Rather than run towards the middle of the pitch with the ball, he can't run with the ball so passed it to someone on the wing, without much space and a fullback to get past. So he went from a huge amount of options and space to run into, to giving Arsenal's break almost no chance. He continued his run with no change of direction, no pace and no pushing the defenders. They knew precisely what was coming and dealt with him easily.
A semi break with Rosicky down the right, he ran at the defence but didn't make them work at all and gave Rosicky no pass, he didn't stop and drop deep into space, nor run across the defender he just ran slightly behind and inbetween both CB's leaving zero passes.
His movement is woeful, his ball control poor, his finishing poor, his decision making extremely poor. A better finisher would have scored many more than him from all the chances this year, and a better player would be less limited and give our attack more avenue's for attack.
He's one of the worst starting strikers I've seen at a top four club for years and years.