The Poland captain was criticised after he and team-mate Nicola Zalewski were spotted getting pictures with the Portugal star.
It came after their side's 5-1 Nations League defeat in Porto on Friday night.
Former defender Jacek Bak slammed the pair, stating: "It's not my thing.
"Times used to be different. We get 5-1 [defeat] and I have to ask Ronaldo for a picture? The guy who f***ed us a moment earlier? Do we really have no honour in us?
"Today, social media is the most important thing and the first one to post a picture with Ronaldo is better? That's not the way to go.
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"Let's say it strongly: coach (Michal) Probierz should react. All that was missing was for him to take a picture with Ronaldo, or maybe swap jackets with Roberto Martinez.
"I guess I'm not cut out for these times. It's sad. I guess I'm cut from a different cloth. Today's world is unfortunately like that."
However, Zielinski has refused to apologise for the pictures as he continues to wear the armband in the absence of the injured Robert Lewandowski.
The Inter Milan midfielder responded: "Nicola and I approached him, asked for a photo and took it. Neither Cristiano nor we had a problem with it, that's all.
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"I am not interested in what's going on in social media. For me, Cristiano Ronaldo is one of the top players in the history of football. I felt like taking a picture and I did. That's it. Why is it unbecoming?
"We lost the match but what should I do? Hide in a corner? I went up to him and asked him for a picture and that's it. That's what I felt like doing.
"He (Bak) has the right to have his own opinion. But I don't think there was anything wrong with it."
Zielinski has won 98 caps for Poland and scored 14 goals since making his debut in 2013.
Manager Michal Probierz has also defended the 30-year-old, adding: "I always tell the players, if you have a problem, if you feel like doing something before the match, take a picture before the match.
"The 90 minutes are of key importance. This time we failed, but we know what to do, how to play, how to work.
"Every player is a human being. We sometimes forget about that. These are people living their lives and they are young people."
Zielinski is expected to continue as captain against Scotland on Monday night.
Lewandowski remains out of contention through injury for the match in Warsaw.
Both sides are still at risk of relegation from League A going into their final Nations League match.