By all means.
That's UAH. That's not ground temperature data. That's atmosphere temperature data.
1998 in particular had a rather strong El Nino that year. And aside from having a large impact on ground temperature data, it had a huge effect on atmospheric temperature.
Despite that, El Nino events only last a fews months at a time. So trying to drag them out into some decades long "trend" would be the height of naivety or malevolence.
And considering the author of that graph is trying to make it look as flat as possible, seems they are trying to be "intentionally misleading" to me.
Or I guess one might be talking about the slight difference between GISS and HadCRU for that year. (But that's not the case this year)